1. The existing foundation pile integrity detection method based on the outer span hole of the pile is characterized by comprising the following steps of:

s1, surrounding an existing foundation pile, drilling and digging two or more groups of detection hole pairs on the ground around the existing foundation pile, wherein each group of detection hole pairs consists of two detection holes; all the detection holes are vertically downward, the depth of the detection holes is greater than the designed pile length of the existing foundation pile, and the distances of any two detection holes on a horizontal plane with any depth are equal;

s2, connecting lines of the same group of detection hole pairs on a horizontal plane with any depth are detection lines, and the detection lines pass through foundation piles and are named as: the first and second detection lines … … have a length L corresponding to the Nth detection line₁、L₂……L_n(ii) a In the same depth horizontal plane, the line segments of the first detection line and the second detection line … …, in which the nth detection line passes through the foundation pile, are respectively: the first pile passing section, the second pile passing section … … Nth pile passing section; non-identical group and adjacentThe connecting line of the two detection holes at the horizontal plane with any depth is a reference line, the reference line is not contacted with the foundation pile, and the reference lines are respectively as follows: the first reference line, the second reference line … … and the Nth reference line have lengths of l₁、l₂……l_n；

S3, installing the transducer of the cross-hole ultrasonic detection equipment at the bottom of each detection hole, keeping the ultrasonic receiving end and the ultrasonic transmitting end of the transducer at the same depth horizontal plane, lifting the transducer upwards to the top of the detection hole, and measuring and recording the depth of each depth horizontal plane as follows: h is₁、h₂……h_mIn the following, the first and second parts of the material,

the sound measured on each detection line is: acoustic time of the first detection line at different depths: t is₁₁、T₁₂……T_1mSecond detection line at different depths of sound: t is₂₁、T₂₂……T_2m… … Nth detection line at different depths is T_n1、T_n2……T_nm(ii) a The lengths of the corresponding first pile passing sections under different depths are set as: d'₁₁、D′₁₂……D′_1mAnd the length of the second pile passing section at different depths is set as: d'₂₁、D′₂₂……D′_2m… … N-th pass pile section length at different depths is set as: d'_n1、D′_n2……D′_nm；

The sound times measured on the reference lines are respectively as follows: the sound time of the first reference line at different depths is t₁₁、t₁₂……t_1mAnd the sound times of the second reference line at different depths are: t is t₂₁、t₂₂……t_2m… … Nth detection line at different depths is t_n1、t_n2……t_nm；

S4, acquiring the propagation velocity V of the ultrasonic wave in the foundation pile_ZAnd the propagation velocity v of the ultrasonic waves in the soil layer in each depth horizontal plane_c1，v_c2……v_cmBy the formula:

D′_nm＝V_z×(T_nm×v_cm-L_n)/(v_cm-V_z)

acquiring the change of each pile passing section under different depth levels;

and S5, reflecting the information of the section and the pile diameter of the foundation pile according to the length of each pile passing section in the same depth horizontal plane, combining the length change of each pile passing section at different depths to obtain the actual pile length of the foundation pile and the variable quantity and the variable position of the pile diameter, and carrying out integrity detection on the existing foundation pile.

2. The existing foundation pile integrity detection method based on the out-of-pile cross hole is characterized in that in step S3, a transducer of a cross hole ultrasonic detection device is installed in front of the bottom of each detection hole, and the method further comprises the following steps:

s31, after drilling and digging a final hole of the detection hole, burying a hard sleeve in the detection hole, wherein the inner diameter of the hard sleeve is larger than the outer diameter of the transducer, and the hard sleeve is vertically downward;

s32, after the hard sleeve is embedded, filling concrete between the outer wall of the hard sleeve and the wall of the detection hole to enable the outer wall of the hard sleeve to be tightly connected with each soil layer;

and S33, filling clear water into the hard sleeve, and continuously maintaining the hard sleeve in a full water state.

3. The existing foundation pile integrity detection method based on the cross-hole outside the pile as claimed in claim 1, wherein the center of the detection line passes through the center of a section of the foundation pile.

4. The existing foundation pile integrity detection method based on the cross-hole outside the pile is characterized in that the detection lines are in three groups relative to the hole, and included angles formed by any two adjacent detection lines are equal.

5. The existing foundation pile integrity detection method based on external cross-hole pile, according to claim 1, characterized in that in step S4, the propagation velocity v of ultrasonic waves in each depth horizontal plane in the soil layer_c1，v_c2……v_cmCan be obtained by the following steps:

s41, measuring the sound time of each reference line on the depth horizontal plane with the depth of m as t through cross-hole ultrasonic detection equipment_1m、t_2m……t_nm(ii) a By the following formula:

and obtaining the propagation speed of the ultrasonic waves in the soil layer in the depth horizontal plane with the depth of m.

6. The existing foundation pile integrity detection method based on external cross-hole pile, according to claim 1, characterized in that in step S4, the propagation velocity v of ultrasonic waves in each depth horizontal plane in the soil layer_c1，v_c2……v_cmCan be obtained by the following steps:

s42, when the cross-hole ultrasonic detection equipment detects that any two sound passing pile sections on the depth horizontal plane with the depth of m are the same in length and the detection lines are different in length, the following steps are respectively carried out: t is_amAnd T_bm(ii) a By the following formula:

and obtaining the propagation speed of the ultrasonic waves in the soil layer in the depth horizontal plane with the depth of m.

7. The existing foundation pile integrity detection method based on the cross-hole outside the pile as claimed in claim 1, wherein in step S4, the propagation velocity V of the ultrasonic wave in the foundation pile is_ZCan be obtained by the following steps:

s43, selecting a depth horizontal plane close to the ground, wherein the distance between the depth horizontal plane and the ground is 0.5-2m, and the propagation speed of the ultrasonic wave in the soil layer of the depth horizontal plane is obtained as v_cmAnd the sound time of each detection line is respectively：T_1m、T_2m……T_nm；

S44, exposing the foundation piles on the depth horizontal plane in an excavation mode, and directly measuring the pile passing section length of each detection line on the depth horizontal plane to be D 'by using a measuring tool'_1m、D′_2m……D′_nmBy the following formula:

and obtaining the propagation speed of the ultrasonic wave in the existing foundation pile.

8. The existing foundation pile integrity detection method based on the outside span hole of the pile is characterized in that the pore diameters of all detection pores are consistent and the pore depth is at least 5m lower than the designed pile of the existing foundation pile.

9. The existing foundation pile integrity detection method based on the external cross hole of the pile as claimed in claim 2, wherein in step S31, after the hard casing is embedded in the detection hole, the method further comprises the following steps:

s311, detecting the hard sleeve by using an inclinometer, and adjusting the hard sleeve according to the slope of the middle through hole of the hard sleeve to enable the middle through hole to be vertically downward.

10. The existing foundation pile integrity detection method based on the external cross-hole of the pile as claimed in claim 1, wherein in step S5, the pile length of the foundation pile can be obtained by the following steps:

s51, measuring the length of the exposed part of the foundation pile and recording the length as L'_s；

S52, according to the change of the length of the pile passing section, the length of any pile passing section is not 0 in the process of lifting the energy converter from bottom to top, the depth of the pile passing section is continuously not 0 in the depth range exceeding 5% of the designed pile length of the foundation pile in the process of depth reduction, or the length of any pile passing section is 0 in the process of moving the energy converter from top to bottom and exceeds the length of the foundation pile in the process of depth increaseThe depth range of the designed pile length 5% is continuously 0, the starting point of the change of the pile section length is recorded, and the depth of the measured starting point position is recorded as L'_x；

According to the formulaObtaining after transformation: d'_nm＝V_z×(T_nm×v_cm-L_n)/(v_cm-V_z) It can be seen that when T is passed_nm×v_cm＝L_nWhen in use, the length of the pile section is 0. This means that the detection line that would have been designed to pass the foundation pile does not substantially pass the foundation pile because the foundation pile is not in this position at this depth level. This is reflected in the case where the sound on the detection line measured by the cross-hole ultrasonic instrument includes only the sound of the ultrasonic wave propagating in the soil layer, and therefore, when the pile diameter-depth curve is judged to be not 0 or suddenly 0, the depth of the point can be judged as the pile bottom position.

S53. actual pile length L ' ═ L ' of foundation pile '_s+L′_x。

Background

The foundation pile is an important structure playing a role in supporting and bearing in a building, and as most of the pile body of the foundation pile is buried underground, the foundation pile has strong concealment, but the problem of difficult detection is brought. As an important part of ensuring the quality and safety of a building, the detection of foundation piles is very important. Whether it is the inspection during construction, the acceptance after completion, or the evaluation of existing piles used for many years. Except that a small part of the exposed pile head can be directly measured by visual observation and tools, most of the pile bodies buried underground need to be detected by indirect means. The buried pile body has the problems of long time consumption, high difficulty, much interference and the like in the detection process due to the influence of surrounding soil layers, and the quantitative integrity detection of the existing foundation pile has great difficulty on the premise of not damaging the existing foundation pile and not influencing the fixation of the existing foundation pile.

The conventional foundation pile detection technology includes: core drilling, low strain dynamic testing, high strain testing and acoustic transmission. Aiming at the existing foundation piles, the existing method has the following defects, such as: the core drilling method can cause local damage to structural concrete of the foundation pile, is a semi-damaged field detection means, is only a hole, and cannot completely describe the integrity of the foundation pile; although the low-strain method can position the pile diameter change area, the pile diameter change cannot be quantitatively reflected, the integrity of the foundation pile cannot be measured, and for a plurality of possible defects of the foundation pile, stress waves formed by detection are mutually superposed to form interference, so that accurate judgment cannot be carried out, and the applicability to the existing foundation pile is poor; the high strain method can only qualitatively describe the defects of the foundation pile and is limited by detection conditions, and the high strain method is not suitable for nondestructive detection of the existing foundation pile; the acoustic transmission method needs to rely on an acoustic pipe pre-buried in the foundation pile, is only suitable for building the foundation pile, cannot describe the pile diameter change of the foundation pile, and cannot judge the defects of diameter expansion and diameter reduction. In summary, the detection of the existing foundation pile is often performed for various reasons, for example, the existing foundation pile is often damaged by common conditions lacking in detection, a detection process, or limitations of a method, so that the integrity of the existing foundation pile cannot be reflected in a detection result, and the integrity detection of the existing foundation pile is difficult to achieve. Therefore, the existing foundation pile detection technology has small dependence on the existing conditions of the foundation pile, does not damage the existing foundation pile and other existing structures, and ensures that the detection result can reflect the integrity of the foundation pile. Therefore, the traditional foundation pile detection method cannot realize the detection of the integrity of the existing foundation pile on the premise of meeting the requirements.

The prior art lacks an effective detection means to existing foundation pile, on the premise of not destroying existing foundation pile, carries out quantitative detection to the integrality of the buried pile body to meet different detection needs, and can detect the integrality of existing foundation pile fast and nondestructively, in time discover the possible damage of existing foundation pile such as: reducing diameter, expanding diameter, breaking and the like, and accurately judging the specific position and degree of damage, thereby providing effective basis for the maintenance, reinforcement or removal of the subsequent foundation pile.

Disclosure of Invention

The invention aims to overcome at least one defect of the prior art and provides an existing foundation pile integrity detection method based on a cross hole outside a pile, which is used for solving the problem of how to perform quantitative integrity detection on the existing foundation pile without damage and quickly.

The invention adopts the technical scheme that the existing foundation pile integrity detection method based on the outer cross hole of the pile comprises the following steps: s1, surrounding an existing foundation pile, drilling and digging two or more groups of detection hole pairs on the ground around the existing foundation pile, wherein each group of detection hole pairs consists of two detection holes; all the detection holes are vertically downward, the hole depth is larger than the designed pile length of the existing foundation pile, and the distances of any two detection holes on a horizontal plane with any depth are the same; s2, the connection line of the same group of detection hole pairs on the horizontal plane with any depth is a detection line, and the detection line passes through foundation piles and respectively comprises the following steps: first detection line, second detection line … … Nth detection line and corresponding lengthAre respectively L₁、L₂……L_n(ii) a In the same depth horizontal plane, the line segments of the first detection line and the second detection line … …, in which the nth detection line passes through the foundation pile, are respectively: the first pile passing section, the second pile passing section … … Nth pile passing section; the connecting line of the two non-identical groups of adjacent detection holes on the horizontal plane with any depth is a reference line, the reference line is not in contact with the foundation pile, and the reference lines are respectively as follows: the first reference line, the second reference line … … and the Nth reference line have lengths of l₁、l₂……l_n(ii) a S3, installing the transducer of the cross-hole ultrasonic detection equipment at the bottom of each detection hole, keeping the ultrasonic receiving end and the ultrasonic transmitting end of the transducer at the same depth horizontal plane, lifting the transducer upwards to the top of the detection hole, and measuring and recording the depth of each depth horizontal plane as follows: h is₁、h₂……h_mNext, the sound times measured on the respective detection lines are: acoustic time of the first detection line at different depths: t is₁₁、T₁₂……T_1mSecond detection line at different depths of sound: t is₂₁、T₂₂……T_2m… … Nth detection line at different depths is T_n1、T_n2……T_nm(ii) a The lengths of the corresponding first pile passing sections under different depths are set as: d'₁₁、D′₁₂……D′_1mAnd the length of the second pile passing section at different depths is set as: d'₂₁、D′₂₂……D′_2m… … N-th pass pile section length at different depths is set as: d'_n1、D′_n2……D′_nm(ii) a The sound times measured on the reference lines are respectively as follows: the sound time of the first reference line at different depths is t₁₁、t₁₂……t_1mAnd the sound times of the second reference line at different depths are: t is t₂₁、t₂₂……t_2m… … Nth detection line at different depths is t_n1、t_n2……t_nm(ii) a S4, acquiring the propagation velocity V of the ultrasonic wave in the foundation pile_ZAnd the propagation velocity v of the ultrasonic waves in the soil layer in each depth horizontal plane_c1，v_c2……v_cmBy the formula: d′_nm＝V_z×(T_nm×v_cm-L_n)/(v_cm-V_z) Acquiring the change of each pile passing section under different depth levels; and S5, reflecting the information of the section and the pile diameter of the foundation pile according to the length of each pile passing section in the same depth horizontal plane, combining the length change of each pile passing section at different depths to obtain the actual pile length of the foundation pile and the variable quantity and the variable position of the pile diameter, and carrying out integrity detection on the existing foundation pile.

The existing ultrasonic technology is only applied to detecting a concrete structure of a foundation pile in a construction process in foundation pile detection, and the cross-hole ultrasonic technology is used for detecting the integral integrity of the existing foundation pile, so that the original foundation pile detection idea is broken through, and a new ultrasonic application and a foundation pile integrity detection method are provided. The integrity detection of the foundation pile mainly comprises the steps of measuring the actual pile length of the existing foundation pile and the change of the pile diameter of the existing foundation pile at different depths.

The method has the advantages that the method does not need to rely on the sound measuring tube which is arranged in the foundation pile under construction in advance, but can be used for detecting the required detection holes on the ground around the foundation pile by drilling, so that the method has stronger adaptability and can be suitable for the existing foundation pile without detection conditions. In the drilling and digging process of the detection hole, the foundation pile can not be influenced, after detection, the detection hole can be sealed in a concrete pouring mode, the influence on the surrounding environment of the foundation pile is basically and completely eliminated, and the real nondestructive detection of the existing foundation pile is realized.

The detection holes are flexibly arranged, can be adjusted in an evading mode according to the actual environment of the site, cannot substantially influence the detection result, and are good in universality and environmental practicability. In the detection process, the transducer is placed at the bottom and then pulled, so that the perpendicularity of the detection hole and the smoothness of a moving path are ensured, and the length of the foundation pile is determined. The ultrasonic receiving end and the ultrasonic transmitting end are positioned on the same horizontal plane, so that the accuracy of the ultrasonic measurement on the detection line or the reference line is guaranteed, and the interference and the error are reduced.

The detection line creates conditions for measuring information of foundation piles and soil layer in the depth horizontal plane, and the reference line creates conditions for measuring information of soil layer in the depth horizontal plane. The propagation speed of the ultrasonic wave in the foundation pile and the propagation speed of the ultrasonic wave in the soil layer of the horizontal plane with any depth can be obtained through various methods, and the actual length of a plurality of pile sections in the horizontal plane with the depth can be obtained through a formula. Through transverse comparison, the lengths of the multiple pile sections in the depth plane are combined with the position arrangement among the detection lines, so that the actual pile diameter in the depth horizontal plane can be quantitatively deduced; through longitudinal comparison, the length change of the same pile passing section at different depths can be used for energetically deducing the pile diameter change of the buried part of the foundation pile and the actual pile length, so that the integrity of the foundation pile is obtained.

In step S3, the method includes the following steps of installing a transducer of the cross-hole ultrasonic testing device in front of the bottom of each testing hole: s31, after drilling and digging a final hole of the detection hole, burying a hard sleeve in the detection hole, wherein the inner diameter of the hard sleeve is larger than the outer diameter of the transducer, and the hard sleeve is vertically downward; s32, after the hard sleeve is embedded, filling concrete between the outer wall of the hard sleeve and the wall of the detection hole to enable the outer wall of the hard sleeve to be tightly connected with each soil layer; and S33, filling clear water into the hard sleeve, and continuously maintaining the full water state in the hard sleeve.

The drilling and digging depth of the detection hole is large, the excessive soil is discharged in the drilling and digging process, the tool collides the hole wall of the detection hole when moving up and down, the hardness of different soil layers is insufficient, and the stability of the detection hole is easy to be insufficient due to various factors such as poor adhesive bonding force between the soil and the like. The more deeply, the overall stability of inspection hole is weaker, and the influence that the passageway that the inspection hole provided receives the environment is big more, appears collapsing of inspection hole more easily, for the passageway in the firm inspection hole, through burying in the inspection hole and put the stereoplasm sleeve pipe, provides the stable passageway of a transducer in the inspection hole, reduces the follow-up dependence of detecting to inspection hole stability.

Concrete is filled between the outer wall of the hard sleeve and the hole wall of the detection hole, so that the hard sleeve is fully fixed, the gap between the hard sleeve and the detection hole is eliminated, and the ultrasonic wave is prevented from being seriously attenuated after passing through an air layer. The hard sleeve is filled with clear water, so that a gap between the transducer and the hard sleeve is further eliminated, and water can keep the non-cavity connection between the transducer and the sleeve in the running process of the transducer, so that the attenuation of ultrasonic waves is reduced.

The connection structure composed of clear water, a hard sleeve and a filled concrete layer enables the transducer to be always in seamless connection with the detection hole in the up-and-down movement process, a good ultrasonic wave propagation channel is formed, the attenuation of ultrasonic waves is reduced, the ultrasonic wave intensity is maintained, errors and interference are reduced, and the test result is more accurate.

The technical scheme is that the center of the detection line passes through the center of a circle of a section of the foundation pile. In the integrity measurement of the existing foundation pile, the length of the pile diameter of the foundation pile at each depth greatly reflects the state of the foundation pile in the horizontal plane of the depth, the length is limited by the exposed range of the foundation pile, and the detection line can only pass through the center of a circle of the section of a certain exposed foundation pile. The length of the pile passing section of the detection line passing through the circle center is consistent with the length of the pile diameter, the length of the pile passing section is the maximum value at the moment, and the change of the pile diameter on the section is directly reflected. Under different depths, the foundation pile can be judged to have defects such as diameter shrinkage, diameter expansion, fracture and the like according to the change of the length of the pile passing section, the specific position and degree of damage can be accurately judged, and even whether the buried part of the foundation pile is inclined or not can be further determined according to experience.

The technical scheme is that the detection hole pairs are three groups, namely three detection lines, and included angles formed by any two detection lines are equal. The defect of one detection line is that the detection line can only reflect the change of the pile diameter length on one straight line, if the foundation pile in the depth plane only has local defects in a certain direction, the single detection line has high probability of being undetected, and theoretically, the more detection lines, the closer the state reflection of the section of the foundation pile is to the real situation. However, in the actual detection process, each more detection line causes more complexity and difficulty in drilling, overall arrangement, operation and analysis, and detection man-hour is delayed.

The three detection lines are adopted, the included angles formed by any two adjacent detection lines are equal, namely when 6 formed angles are all 60 degrees, the detection lines are uniformly distributed in the depth horizontal plane, the possibility that defects are ignored is greatly reduced, meanwhile, the specific bending direction of the foundation pile can be judged according to experience, and the integrity test of the foundation pile is more comprehensive and accurate.

In step S4, the propagation velocity v of the ultrasonic waves in the soil layer in each depth horizontal plane is determined_c1，v_c2……v_cmCan be obtained by the following steps: s41, measuring the sound time of each reference line on the depth horizontal plane with the depth of m as t through cross-hole ultrasonic detection equipment_1m、t_2m……t_nm(ii) a By the following formula:and obtaining the propagation speed of the ultrasonic waves in the soil layer in the depth horizontal plane with the depth of m.

The propagation speed of the ultrasonic wave in the soil layer in the depth horizontal plane with the depth of m can be obtained by calculation through the existing detection environment, the measurement is convenient, even if the existing foundation pile without the exposed part can be measured by adopting the method, and the applicability is strong. The reference line surrounds the existing foundation pile, end-to-end annular detection rings are formed around the foundation pile, the propagation time of the ultrasonic waves in soil layers around the foundation pile is obtained through a calculation method of averaging after measurement of each section, the measurement range is wide, and the anti-interference performance is high. It is worth noting that the propagation speed of the ultrasonic wave in the soil layers of different depth levels changes continuously along with the structure of the soil layer, so that the propagation speed of the ultrasonic wave in each depth level needs to be calculated again.

In step S4, the propagation velocity v of the ultrasonic waves in the soil layer in each depth horizontal plane is determined_c1，v_c2……V_cmCan be obtained by the following steps: s42, when the cross-hole ultrasonic detection equipment detects that any two sound passing pile sections on the depth horizontal plane with the depth of m are the same in length and the detection lines are different in length, the following steps are respectively carried out: t is_amAnd T_bm(ii) a By the following formula:obtaining the depth level of the ultrasonic wave at the depth of mThe propagation velocity of the inner earth layer.

Under specific conditions, the propagation speed of the ultrasonic waves in the soil layer in the depth horizontal plane can be calculated by utilizing two detection lines which have the same length of the pile passing section but different overall lengths, the method depends on that the pile passing section can be directly measured, enough exposed parts of foundation piles are required, and the detection method greatly simplifies the calculation process and the accuracy of the propagation speed of the ultrasonic waves in the soil layer in the depth horizontal plane. The scheme is more suitable for soil layer detection with smaller depth.

In step S4, the propagation velocity V of the ultrasonic wave in the foundation pile is determined_ZCan be obtained by the following steps: s43, selecting a depth horizontal plane close to the ground, wherein the distance between the depth horizontal plane and the ground is 0.5-2m, and the propagation speed of the ultrasonic wave in the soil layer of the depth horizontal plane is obtained as v_cmAnd the acoustic time T of each detection line_1m、T_2m……T_nm(ii) a S44, exposing the foundation piles on the depth horizontal plane in an excavation mode, and directly measuring the pile passing section length of each detection line on the depth horizontal plane to be D 'by using a measuring tool'_1m、D′_2m……D′_nmBy the following formula:and obtaining the propagation speed of the ultrasonic wave in the existing foundation pile.

The propagation speed of the ultrasonic wave in the foundation pile can be based on the detection condition set outside the foundation pile by the method, and on the existing detection condition, the position of the foundation pile is selected and measured at the position close to the ground, wherein the position is 0.5-2m away from the ground, and the significance of the range is that the subsequent excavation operation is facilitated while the earth surface is prevented from loosening a mud layer. Firstly, measuring the sound time of each detection line and each reference line, and after the measurement is finished, actually measuring the accurate parameters at the measurement position of the foundation pile by using an excavation mode, thereby calculating the propagation speed of the ultrasonic waves in the foundation pile. The speed is a fixed value by default, and the whole concrete structure in the foundation pile is consistent by default, so that the ultrasonic propagation speed V of the foundation pile under any depth level is no matter_zAll are unchanged, and the ultrasonic propagation velocity v of the foundation pile_zOnly one calculation is needed.

The technical scheme is that the hole diameter of the detection hole is consistent, and the hole depth is at least 5m lower than the designed pile of the existing foundation pile. The depth of detection is not less than 5m for the increase of design pile length, and one of them, the depth downward extending ensures that the buried pile body part can be completely scanned to ensure that the possible foundation pile which is not built according to the design or the foundation pile sinks due to various reasons, and the like, the hole of the downward extending depth can provide enough detection allowance, and the detection of the pile length of the foundation pile can not be completed when the lowest depth is reached. The foundation pile under the soil layer has the concealment performance, the position connected nearby can be inevitably changed after a certain position is influenced, the depth is prolonged, on one hand, the detection range is not blindly increased, so that the consumed working hours are caused, on the other hand, the whole foundation pile can be comprehensively and effectively reflected, the defects of abnormal increase and deepening caused by fracture or separation reasons of the foundation pile are prevented, the time loss caused by secondary drilling and digging of the detection hole is avoided, and the quantitative depth increase and the proper depth increase are realized.

In the technical scheme, in the step S31, after the hard sleeve is embedded in the detection hole, the method further comprises the following steps: s311, detecting the hard sleeve by using an inclinometer, and adjusting the hard sleeve according to the slope of the middle through hole of the hard sleeve to enable the middle through hole to be vertically downward. The slope of the hard sleeve is detected, so that the verticality of a moving channel of the transducer is ensured, errors caused by the detection process are reduced, the transmission of ultrasonic waves is stabilized, and the sound of each detection line and the sound of the reference line are accurate.

In the technical scheme, in the step S5, the pile length of the foundation pile can be obtained through the following steps: s51, measuring the length of the exposed part of the foundation pile and recording the length as L'_s(ii) a According to the change of the length of the pile passing section, the length of any pile passing section is not 0 in the process that the transducer is lifted from bottom to top, the depth range exceeding 5% of the designed pile length of the foundation pile is continuously not 0 in the process that the depth is reduced, or the length of any pile passing section is 0 in the process that the transducer moves from top to bottom, the depth range exceeding 5% of the designed pile length of the foundation pile is continuously 0 in the process that the depth is increased, and the change of the length of the pile passing section is recordedStarting point of chemical conversion, depth of measured starting point location is recorded as L'_x(ii) a . S53. actual pile length L ' ═ L ' of foundation pile '_s+L′_x。

According to the formulaObtaining after transformation: d'_nm＝V_z×(T_nm×v_cm-L_n)/(v_cm-V_z) It can be seen that when T is passed_nm×v_cm＝L_nWhen in use, the length of the pile section is 0. This means that the detection line that would have been designed to pass the foundation pile does not substantially pass the foundation pile because the foundation pile is not in this position at this depth level. This is reflected in the case where the sound on the detection line measured by the cross-hole ultrasonic instrument includes only the sound of the ultrasonic wave propagating in the soil layer, and therefore, when the pile diameter-depth curve is judged to be not 0 or suddenly 0, the depth of the point can be judged as the pile bottom position.

Compared with the prior art, the invention has the beneficial effects that: the method has small requirements on the detection conditions of the existing foundation pile, has strong applicability, can be used for the existing foundation pile, and is also suitable for building the foundation pile. According to the method, a plurality of pairs of detection holes are drilled on the ground outside the foundation pile, so that secondary damage to the foundation pile possibly caused in the detection process is avoided in the form of detecting the required conditions of the member outside the foundation pile. The detection process of the foundation pile is controllable, the sections of the foundation piles under the horizontal planes with different continuous depths can be comprehensively detected, the pile length of the foundation pile is quantitatively reflected, the change of the pile diameter of the foundation pile under the continuous depths is obtained, the problems of diameter shrinkage, diameter expansion, breakage and the like of the foundation pile are accurately judged, and the specific position of the problem is determined. The method has strong anti-interference performance, and provides a powerful basis for the subsequent maintenance, reinforcement or removal of the foundation pile through the accurate and quantized integrity detection data.

Drawings

FIG. 1 is a schematic view of the construction of a foundation pile and a manhole in the ground in the method of the present invention.

FIG. 2 is a schematic diagram of the arrangement of two sets of detection paired holes in the method of the present invention.

FIG. 3 is a schematic view of the structure of a detection pore in the method of the present invention.

FIG. 4 is a schematic diagram of the arrangement of three sets of detection wells in the method of the present invention.

Fig. 5 is a graph showing the relationship between the pile passing section and the depth after the integration of the length of the pile passing section according to embodiment 2 of the method of the present invention.

FIG. 6 is a graph showing the relationship between the time and depth of the detection line sound measured in example 2 according to the method of the present invention.

Fig. 7 is a schematic view of the deformation of the foundation pile analytically presumed from fig. 5 in embodiment 2 of the method of the invention.

Description of reference numerals: the detection device comprises a first detection hole 201, a second detection hole 202, a third detection hole 203, a fourth detection hole 204, a fifth detection hole 205, a sixth detection hole 206, a first detection line 301, a first pile passing section 311, a second detection line 302, a second pile passing section 312, a third detection line 303, a third pile passing section 313, a first reference line 401, a second reference line 402, a third reference line 403, a fourth reference line 404, a fifth reference line 405, a sixth reference line 406, a foundation pile 101, a detection hole 102, a ground 103, concrete mortar 121, a hard casing 122, a middle through hole 123, clean water 124, a soil layer 104, a first position 801, a second position 802, a third position 803 and a fourth position 804.

Detailed Description

The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

Example 1

As shown in fig. 2, the present embodiment is a method for detecting the integrity of an existing foundation pile 101 based on a hole spanning outside the pile, and the method includes the following steps: more than two sets of inspection hole pairs are drilled in selected unobstructed positions on the ground surface 103 around the foundation pile 101, around and as close as possible to the existing foundation pile 101. Each set of test pair holes consists of two test holes 102, all test holes 102 facing vertically downward. The designed pile length of the existing foundation pile 101 is obtained by looking up engineering data, the hole depth of the detection hole 102 exceeds the designed pile length of the existing foundation pile 101 by more than 5m, and the distance between any two detection holes 102 on a horizontal plane with any depth is the same.

As shown in FIG. 1, the connecting line of the same group of detection hole pairs at any depth horizontal plane is named as a detection line, the detection line passes through the foundation pile 101, the part of the detection line passing through the foundation pile 101 is a pile passing section, and the detection line can be respectively named as: the lengths of the first detection line 301, the second detection line 302 … … and the Nth detection line are consistent under different depth levels. And the line segment of the first detecting line 301 passing through the foundation pile 101 in the cross section of the foundation pile 101 is named as a first pile passing section 311, the part of the second detecting line 302 passing through the foundation pile 101 is named as a second pile passing section 312, and similarly … …, the part of the nth detecting line passing through the foundation pile 101 is named as an nth pile passing section. And constructing at the position of the pile head of the foundation pile 101 to form a flat construction plane, wherein the construction plane at least covers the position of the detection hole 102 to be drilled. The foundation pile 101 at the construction plane is exposed, the pile diameter of the foundation pile 101 at the construction plane is directly measured to be R through a tool, the detection hole 102 is arranged, the center of the detection line passes through the center of the section of the foundation pile 101 on the construction plane, and the included angle formed by any two adjacent detection lines is further made to be equal.

The connecting line of two adjacent detection holes 102 in the non-same group at any depth level is a reference line, and the reference line is not in contact with the foundation pile 101. The distance of the reference line from the foundation pile 101 should be as short as possible, but not less than 0.5 times the diameter length of the inspection hole 102. The reference lines are connected end to end forming a ring reference around the foundation pile 101. The reference lines are respectively named: first reference line 401, second reference line 402 … … nth reference line.

As shown in fig. 3, the inspection holes 102 are drilled at predetermined positions, and after finishing the holes, the hard casing 122 is buried in the inspection holes 102, wherein the inspection holes 102 are circular holes, and the diameters of all the inspection holes 102 are equal and larger than the outer diameter of the hard casing 122 to be buried. The inner diameter of the hard sleeve 122 needs to be larger than the outer diameter of the transducer, with the hard sleeve 122 facing vertically downward. The hard sleeve 122 is detected by an inclinometer, and the hard sleeve 122 is adjusted according to the slope of the middle through hole 123 of the hard sleeve 122, so that the middle through hole 123 is kept vertically downward. Concrete is filled between the outer wall of the hard sleeve 122 and the hole wall of the detection hole 102, concrete mortar 121 which is quick to dry can be adopted, the outer wall of the hard sleeve 122 is tightly connected with each soil layer 104, clear water 124 is filled in the hard sleeve 122 after the concrete is solidified, and the clear water 124 in the hard sleeve 122 is continuously maintained in a full water state in the detection process.

Each detection line is directly measured, and the length corresponding to the first detection line 301 is L₁The length corresponding to the second detection line 302 is L₂… … similarly, the length of the Nth detection line is L_nThe length of each detection line is controlled to be not more than two times of R as much as possible. Each reference line is directly measured, and the length corresponding to the first reference line is l₁The length corresponding to the second reference line is l₂… … for the same reason, the Nth reference line has a length l_n。

The method comprises the steps of vertically installing transducers connected with cross-hole ultrasonic detection equipment at the bottoms of all detection holes 102, keeping ultrasonic receiving ends and ultrasonic transmitting ends of the transducers at the same depth level, lifting the transducers upwards to the tops of the detection holes 102, continuously supplementing clear water 124 into a hard sleeve 122 in the lifting process, adopting uniform-speed lifting, and sampling at certain depth intervals. And measuring and recording the depths of the pressed parts upwards in each depth horizontal plane as follows: h is_1、h₂……h_mIn the depth horizontal plane at each depth, the sound measured on each detection line is: first detection line 301 at different depths of sound: t is₁₁、T₁₂……T_1mSecond detection line 302 at different depths of sound: t is₂₁、T₂₂……T_2m… … Nth detection line at different depths is T_n1、T_n2……T_nm(ii) a The lengths of the corresponding first pile passing section 311 at different depths are set as: d'₁₁、D′₁₂……D′_1mThe lengths of the second pile passing section 312 at different depths are set as: d'₂₁、D′₂₂……D′_2m… … N-th pass pile section length at different depths is set as: d'_n1、D′_n2……D′_nm；

The sound times measured on the reference lines are respectively as follows: the first reference line 401 is t at sound times at different depths₁₁、t₁₂……t_1mSecond reference line 402 for sounds at different depths is: t is t_21、t₂₂……t_2m… … Nth detection line at different depths is t_n1、t_n2……t_nm(ii) a Let v be the propagation velocity of ultrasonic waves in the soil layer 104 in each depth horizontal plane_c1，v_c2……V_cm. The sound time of each reference line is respectively as follows: t is t_1m、t_2m……t_nmWhere m corresponds to the depth and n corresponds to the designation of the reference line. When the depth is m, the propagation speed of the ultrasonic wave in the depth horizontal plane in the soil layer 104 is

Further selecting a depth horizontal plane close to the ground 103, wherein the distance between the depth horizontal plane and the ground 103 is 0.5-2m, so that m is 0.5-2m, and obtaining the sound of each detection line respectively comprises the following steps: t is_1m、T_2m……T_nmWhere m corresponds to depth and n corresponds to the naming of the detection lines. Acquiring the propagation velocity v of the ultrasonic wave at the depth m in the soil layer 104_cmThe foundation pile 101 at the depth of m is exposed by excavation, and the pile passing length of each detection line at the depth level is directly measured by a measuring tool as D'_1m、D′_2m…D′_nmThe propagation velocity of the ultrasonic wave in the existing foundation pile 101 is

The pile passing section length of each detection line under each depth is D'_nm＝V_z×(T_nm×v_cm-L_n)/(v_cm-V_z). The length of the exposed portion of foundation pile 101 was measured and recorded as L'_s. And according to the change of the length of the pile passing section, finding the depth position of 0 or 0 after the sudden reduction of the length of the pile passing section.

Recorded as L'_xActual pile length L ' ═ L ' of foundation pile 101 '_s+L′_x。

The method comprises the steps of analyzing the change of the section and the pile diameter of the foundation pile 101 according to the length of each pile passing section in the same depth horizontal plane, judging whether the foundation pile 101 has the problems of diameter reduction, diameter expansion, breakage and the like under one depth or a plurality of depths, accurately judging the specific position and degree of damage, further determining whether the buried part of the foundation pile 101 is inclined according to experience, and forming the integrity test of the foundation pile 101 by combining pile length information.

Example 2

As shown in fig. 4, the present embodiment measures an existing foundation pile 101 to be tested by using an existing foundation pile 101 integrity testing method based on pile-out cross holes, and drills three sets of test hole pairs around and as close as possible to the existing foundation pile 101 at selected locations on the ground 103 around the foundation pile 101 that are free from obstacles. Every group detects to constitute by two inspection holes to the hole, specifically is: a first test well 201, a second test well 202, a third test well 203, a fourth test well 204, a fifth test well 205, and a sixth test well 206. All the detection holes are vertically downward. The designed pile length of the existing foundation pile 101 is 15m obtained by looking up engineering data, the hole depth of the detection hole exceeds the designed pile length of the existing foundation pile 101, the hole depth is 20m, and the distance between any two detection holes on a horizontal plane with any depth is the same.

The first detection hole 201 and the fourth detection hole 204 are a group and named as a first detection pair hole; the second detection hole 202 and the fifth detection hole 205 are a group and named as a second detection paired hole; the third detection hole 203 and the sixth detection hole 206 are a set, and named as a third detection pair hole. The first detection pair holes form a first detection line 301, the second detection pair holes form a second detection line 302, and the third detection pair holes form a third detection line 303. The first and second detection holes 201 and 202 form a first reference line 401, the second and third detection holes 202 and 203 form a second reference line 402, the third and fourth detection holes 203 and 204 form a third reference line 403, the fourth and fifth detection holes 204 and 205 form a fourth reference line 404, the fifth and sixth detection holes 205 and 206 form a fifth reference line 405, and the sixth and first detection holes 206 and 201 form a sixth reference line 406. The same detection line has the same length in different depth levels, the line segment of the first detection line 301 passing through the foundation pile 101 in the section of the foundation pile 101 is named as a first pile passing section 311, the part of the second detection line 302 passing through the foundation pile 101 is named as a second pile passing section 312, and the part of the third detection line 303 passing through the foundation pile 101 is named as a third pile passing section 313. And constructing at the position of the pile head of the foundation pile 101 to form a flat construction plane, wherein the construction plane at least covers the position of the detection hole 102 to be drilled. The foundation pile 101 at the construction plane is exposed, the pile diameter of the foundation pile 101 at the construction plane is directly measured to be 1m through a tool, the detection hole 102 is arranged, the center of the detection line passes through the center of the section of the foundation pile 101 on the construction plane, and the included angle formed by any two adjacent detection lines is further made to be equal. The reference line is not in contact with the foundation pile 101 and the reference lines are connected end to end forming a ring reference around the foundation pile 101.

And drilling and digging detection holes 102 according to preset positions, wherein the diameters of the detection holes 102 are consistent and are all 150 mm. And after finishing the hole, burying a 4-inch long PVC hard pipe in the detection hole 102, wherein the length of the PVC hard pipe is 20.5 m. The PVC hard pipe is vertically downward. The PVC hard pipe is detected by utilizing an inclinometer, and the PVC hard pipe is adjusted according to the slope of the middle through hole 123 of the PVC hard pipe, so that the middle through hole 123 is kept vertically downward. Concrete is filled between the outer wall of the PVC hard pipe and the hole wall of the detection hole 102, concrete mortar 121 which is quick to dry can be adopted, the outer wall of the PVC hard pipe is tightly connected with each soil layer 104, clear water 124 is filled in the PVC hard pipe after the concrete is solidified, and the clear water 124 in the PVC hard pipe is continuously maintained in a full water state in the detection process.

And each detection line is directly measured, the length corresponding to the first detection line 301 is 2m, the length corresponding to the second detection line 302 is 1.4m, the length corresponding to the third detection line 303 is 1.4m, and the lengths of the first pile passing section 311, the second pile passing section 312 and the third pile passing section 313 are equal and equal to 1 m. First reference line 401, third reference line 403, fourth reference line 404 and sixth reference line 406 are each 0.84m long, and second reference line 402 and fifth reference line 405 are each 0.65m long. The included angle between the first detection line 301 and the second detection line 302 is 60 degrees, the included angle between the first detection line 301 and the third detection line 303 is 60 degrees, and the included angle between the second detection line 302 and the third detection line 303 is 60 degrees.

The method comprises the steps of vertically installing transducers connected with cross-hole ultrasonic detection equipment at the bottoms of all detection holes 102, keeping ultrasonic receiving ends and ultrasonic transmitting ends of the transducers at the same depth level, lifting the transducers upwards to the tops of the detection holes 102, continuously supplementing clear water 124 into a hard sleeve 122 in the lifting process, adopting uniform-speed lifting, and sampling at an interval of 200 mm.

Further, a depth horizontal plane close to the ground 103 is selected, the distance between the depth horizontal plane and the ground 103 is 1.4m, the sound time of the first detection line 301 is 727ms, the sound time of the second detection line 302 is 438ms, and the sound time of the third detection line 303 is 436 ms. Excavating soil with a certain depth near the foundation pile 101 to expose the foundation pile 101 at the position of 1.4m, measuring the depth, wherein the first pile passing section 311, the second pile passing section 312 and the third pile passing section 313 are all 1m, and adopting a formula

The propagation speed of the ultrasonic waves in the soil layer 104 at the depth level is 2073 m/s. Combination formula The propagation speed of the ultrasonic wave in the foundation pile 101 was obtained to be 4120 m/s.

Adopting a formula D'_nm＝V_z×(T_nm×v_cm-L_n)/(v_cm-V_z) And calculating the lengths of the pile sections passing through each detection line at each depth. After integration, as shown in fig. 5, fig. 5 shows that the pile passing section changes with the depth, and from the first position 801 of the curve, the pile body at a position 1039m away from the ground surface has a reduced diameter and shrinks by 212 mm; from the second position 802 of the curve, the pile body at a position 10312m away from the ground is expanded by 234 mm; from the third position 803 of the curve, it can be seen that the position 10314.6m away from the ground is the pile bottom, i.e., L'_xWhen the pile head is completely exposed, the length of the foundation pile 101 is 14.6m, the length of the actual pile is 0.2m, and the actual pile length is 14.8 m. As shown in fig. 6, the variation of the wave in sound coincides with the variation of the pile passing section.

Further analysis shows that, as shown in fig. 5, at the fourth position 804, the first detection line 301 is stable in a range from 1033.4m to 5.2m away from the ground, and the lengths of the second detection line 302 and the third detection line 303 are obviously reduced. And then returning to the three detection lines to return to the normal state, judging that the foundation pile 101 is likely to deform in the range of 1033.4m to 5.2m away from the ground, and as shown in fig. 7, the deformation protrusion part is inclined to the direction of the first detection line 301, and the second detection line 302 and the third detection line 303 are not deviated from the circle any more due to the position change, so that the second pile passing section 312 and the third pile passing section 313 are reduced.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.