Loss testing method and repairing method for dynamic sounding energy of gravel pile

Abstract

The invention provides a loss test method for dynamic sounding energy of a gravel pile, and the method comprises the following steps: building a preset detection platform, and arranging a dynamic strain sensor and an acceleration sensor on a probe rod of to-be-carried dynamic sounding equipment; performing a hammering test on the gravel pile based on a preset hammering method through dynamic sounding equipment, and obtaining primary test data; the dynamic sounding equipment is carried on a detection platform, then a hammering test is carried out on the gravel pile based on a preset hammering method, secondary test data are obtained, and the test data comprise dynamic strain data, acceleration data and hammering number data; and processing the primary test data and the secondary test data according to a preset analysis method so as to calculate the rod length correction coefficient of the probe rod. Compared with the prior art, the testing accuracy and effectiveness of dynamic sounding in the field of geotechnical in-situ testing can be improved.

Description

Technical Field

[0001] The invention relates to a monitoring device, in particular to a loss testing method and a repairing method for dynamic penetration energy of a gravel pile. Background Art

[0002] In the field of geotechnical in-situ testing, dynamic penetration testing is an extremely important and widely used testing method. It has the remarkable characteristics of simple testing process and good adaptability to various complex geological conditions. It plays an irreplaceable and key role in the evaluation of the characteristics of different types of foundations such as clay, silt, sand and gravel soil. Internationally, the test results of dynamic penetration testing are often used as an important basis for estimating the CBR strength or stiffness modulus of materials, which shows the wide and valuable applicability of its results. Among them, many factors can have a substantial impact on the test results of dynamic penetration testing, such as: the verticality of the core hammer when it falls, the depth involved in the test, the angle presented by the cone tip, the weight of the hammer itself, the lifting height of the hammer, the water content inside the soil, the particle composition structure and strength characteristics of the tested soil, and the compactness of the soil.

[0003] When carrying out the density test of gravel soil, a heavy-duty dynamic penetration test is usually used. In this test, the weight of the hammer used is set to 63.5kg, the lifting height of the hammer is determined to be 76cm, and the cone tip angle is 60°. In the process of testing specific gravel soil, after in-depth research and practice, it is found that the verticality of the hammer when it falls and the test depth are the main factors affecting the change. As for the verticality of the hammer falling, it is necessary to use a special verticality control system to effectively control it within the accuracy range required by the relevant specifications, so its impact on the final test results is relatively limited. As for the factor of test depth, with the continuous change of test depth, the rod length corresponding to the penetration equipment will also change accordingly. According to Newton's inelastic collision theory, the change of rod length will cause a significant change in the energy obtained by the penetration system after the collision. For this reason, the number of hammer blows obtained at different depths must be accurately corrected in order to more accurately evaluate the strength or density of the soil. Moreover, the hammer blow correction method used in the current "Geotechnical Engineering Investigation Code" is mainly based on data collected by conducting dynamic penetration tests in different regions and using electrical measurement methods during the period from 1984 to 1988. However, this correction method also has obvious defects. For example, the correction data for the rod length is obtained by testing at different depths. In this process, in addition to the influence of the rod length itself, many factors such as the soil density and overburden stress of the soil layers at different depths will also interfere with the test results simultaneously, which undoubtedly brings great complexity and challenges to the subsequent data analysis. In addition, the electrical measurement equipment used during the period from 1984 to 1988 was relatively simple, and its dynamic response frequency was at a low level, which greatly reduced the reliability of the data obtained by the test and made it difficult to meet the current urgent demand for high-precision test results.

[0004] To sum up, the existing dynamic penetration test technology and the hammer number correction method in the relevant specifications have exposed many problems that need to be solved urgently when facing complex engineering practice requirements. Therefore, how to provide a more accurate, reliable and efficient improvement plan to improve the test accuracy and effectiveness of dynamic penetration in the field of geotechnical in-situ testing is a technical problem that the present invention urgently needs to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a method for testing the energy loss of dynamic penetration test of gravel piles and a repair method so as to improve the accuracy and effectiveness of dynamic penetration test in the field of geotechnical in-situ testing.

[0006] In order to achieve the above object, the present invention provides a method for testing the loss of energy of dynamic penetration of a stone pile, comprising:

[0007] Build a preset detection platform, and set a dynamic strain sensor and an acceleration sensor on the probe rod of the dynamic penetration equipment to be carried;

[0008] Perform hammer tests on gravel piles using dynamic penetration equipment based on a preset hammering method and obtain initial test data;

[0009] The dynamic penetration equipment is mounted on the detection platform, and then a hammer test is performed on the gravel pile based on the preset hammering method, and secondary test data is obtained. Secondly, the test data includes: dynamic strain data, acceleration data, and hammering number data;

[0010] According to a preset analysis method, the initial test data and the secondary test data are processed to calculate the rod length correction coefficient of the probe rod.

[0011] Further preferably, the preset hammering method includes: within the preset depth, hammering is performed according to the position where the preset interval distance is located, and a set of the test data obtained is recorded, and outside the preset depth, multiple hammering is performed according to the position where the interval distance is located, and the test data obtained by each hammering is recorded.

[0012] Further preferably, the preset depth is 20 m and the distance is 1 m.

[0013] Further preferably, according to a preset analysis method, the step of processing the initial test data and the secondary test data to calculate the correction coefficient of the probe rod includes:

[0014] According to a preset speed and energy correlation algorithm, the initial test data and the secondary test data are calculated to obtain the initial detection energy transfer efficiency and the secondary detection energy transfer efficiency;

[0015] The rod length correction coefficient is calculated according to the ratio of the primary detection energy transfer efficiency to the secondary detection energy transfer efficiency.

[0016] Further preferably, the rod length correction coefficient calculation formula is ETR1 / ETR2; wherein ETR1 represents the energy transfer efficiency of the primary detection, and ETR2 represents the energy transfer efficiency of the secondary detection.

[0017] Further preferably, the speed and energy correlation algorithm is FV analysis method.

[0018] Further preferably, the detection platform is a support platform built on land and / or a platform on water.

[0019] Further preferably, when the detection platform is an above-water platform, the detection platform follows the rise and fall of the tide, and at different rising positions of the tide, performs the preset hammering method on the gravel piles at the same reference position to respectively obtain the initial test data and the secondary test data; wherein the above-water platform is a support platform set on a ship on the sea surface or a tidal river section.

[0020] Further preferably, the hammering positions corresponding to the initial test data and the secondary test data are used to obtain the tidal difference corresponding to at least 3m;

[0021] And / or, the tidal difference is 15-25% of the rod length of the probe rod.

[0022] Further preferably, when the detection platform is a support platform built on land, the height of the support platform and / or the foundation pit depth of the gravel piles are adjusted to thereby implement testing of gravel piles of different depths;

[0023] And / or, the height between the dynamic penetration equipment on the detection platform and the gravel pile is 15-25% of the length of the probe rod.

[0024] Further preferably, after the step of processing the initial test data and the secondary test data according to a preset analysis method to calculate the rod length correction coefficient of the probe rod, the method further includes:

[0025] Obtaining a first rod length correction coefficient and a second rod length correction coefficient, wherein the first rod length correction coefficient is obtained according to a land platform test, and the second rod length correction coefficient is obtained according to a water platform test;

[0026] According to a preset weighting algorithm and weighting factor, the first rod length correction coefficient and the second rod length correction coefficient are weighted to obtain an initial rod length correction coefficient;

[0027] According to the initial rod length correction coefficient, the detection energy transfer efficiency data to be verified is calculated;

[0028] Comparing and analyzing the detection energy transfer efficiency data to be verified and the detection energy transfer efficiency data acquired in real time, and calculating the difference;

[0029] If the difference is not within the error range, the weighting factor is corrected according to the preset correction factor, and the corrected rod length correction coefficient is obtained, and the above test is continued in a loop until the difference is within the error range, then the verification test is stopped, and the updating of the rod length correction coefficient is stopped;

[0030] If the difference is within the error range, the initial rod length correction factor is determined to be the rod length correction factor.

[0031] Compared with the prior art, the present application provides a method for testing the energy loss of dynamic penetration of gravel piles, so as to improve the accuracy and effectiveness of dynamic penetration in the field of geotechnical in-situ testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic flow chart of a method for testing the energy loss of dynamic penetration of a stone pile proposed in the first embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of a specific flow chart of step S40 in the first embodiment of the present invention;

[0034] Figure 3 It is a schematic structural diagram of a support platform in a first embodiment of the present invention;

[0035] Figure 4 This is a structural schematic diagram of a schematic diagram of a detection platform disposed on a ship in a first embodiment of the present invention;

[0036] Figure 5 FIG. 1 is a flow chart of steps S50 to S110 in the third embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific embodiment:

[0039] Embodiment 1

[0040] like Figures 1 to 3 As shown, this embodiment provides a method for testing the loss of energy of dynamic penetration of a gravel pile, comprising:

[0041] Step S10, build a preset detection platform, and set a dynamic strain sensor and an acceleration sensor on the probe rod of the dynamic probing equipment to be mounted; wherein the dynamic strain sensor and the acceleration sensor are electrically connected to an external test terminal, and the test terminal is set on the dynamic probing equipment, or can be independently set outside. In addition, a program is set in the test terminal, which can analyze and calculate the test data obtained by the dynamic strain sensor and the acceleration sensor, etc., to obtain the hammer number data and the rod length correction coefficient, etc., which will not be specifically described and limited here.

[0042] Step S20: Performing a hammer test on the gravel pile using a dynamic probing device based on a preset hammering method, and obtaining initial test data;

[0043] Step S30, the dynamic penetration equipment is mounted on the detection platform, and then a hammer test is performed on the gravel pile based on the preset hammering method, and secondary test data is obtained. Secondly, the test data includes: dynamic strain data, acceleration data, and hammering number data;

[0044] Step S40: Process the initial test data and the secondary test data according to a preset analysis method to calculate a rod length correction coefficient of the probe rod.

[0045] From the above content, it can be seen that the above method can make full use of the height difference of the platform or the tidal difference of the rising and falling tides in the sea, and the drop hammer will not be affected by factors such as soil density and soil particle grading during the movement of this high space. Therefore, during the test, it can better reduce the influence of factors such as the overlying soil pressure in the gravel pile or the soil layer above it, the soil density, the soil particle grading and other factors on the rod length hammer coefficient and the hammer efficiency, so as to minimize the influence of other factors on the test results of the hammer efficiency, so as to better analyze the influence of the rod length on the number of dynamic sounding hammer blows and the hammer efficiency, so as to more accurately calculate the rod length hammer coefficient, so as to improve the test accuracy and effectiveness of dynamic sounding in the field of geotechnical in-situ testing.

[0046] In addition, it is worth mentioning that the power probing equipment in this embodiment can preferably be a heavy-duty power probing instrument. Of course, in practical applications, it can also be a light-duty power probing instrument, an ultra-heavy-duty power probing instrument, or a YZS-3 fully automatic hydraulic heavy-duty power probing instrument, etc.

[0047] Further preferably, the preset hammering method includes: within a preset depth, hammering is performed according to the position of a preset interval distance, and a set of acquired test data is recorded, and outside the preset depth, multiple hammering is performed according to the position of the interval distance, and the test data acquired from each hammering is recorded.

[0048] Further preferably, the preset depth is 20 m and the distance is 1 m.

[0049] Further preferably, Figure 2 As shown, according to a preset analysis method, the step of processing the initial test data and the secondary test data to calculate the correction coefficient of the probe rod, that is, step S40, also includes:

[0050] Step S401: Calculate the initial test data and the secondary test data according to a preset speed and energy correlation algorithm, and obtain the initial detection energy transfer efficiency and the secondary detection energy transfer efficiency;

[0051] Step S402: Calculate the rod length correction coefficient according to the ratio of the primary detection energy transfer efficiency to the secondary detection energy transfer efficiency.

[0052] Further preferably, the speed and energy correlation algorithm is FV analysis method.

[0053] For example, the calculation formula of the rod length correction coefficient ξ(i) in this embodiment may preferably be ETR1 / ETR2;

[0054] in, EMX=max[E (t) (t)]; E (t) (t)=∫F(t)du=∫F(t)v(t)dt; E R =mgh; m is the mass of the falling hammer used for the impact test; h is the impact test height of the falling hammer; g is the acceleration of gravity; t is the instantaneous time of the hammer impact; ETR is the hammer impact efficiency; ETR1 represents the energy transfer efficiency of the primary detection, and ETR2 represents the energy transfer efficiency of the secondary detection.

[0055] Further preferably, the detection platform is a support platform built on land.

[0056] Further preferably, when the detection platform is a support platform built on land, the height of the support platform and / or the foundation pit depth of the gravel piles are adjusted to thereby implement testing of gravel piles at different depths.

[0057] In addition, as a preferred method, the height of the support platform in this embodiment is preferably 3 to 4 meters, and the height of the height space is prevented from being too short to cause a test error.

[0058] Further preferably, the height of the support platform is preferably 5 to 6 m.

[0059] Further preferably, the height between the dynamic probing equipment located on the detection platform and the gravel pile is 15-25% of the rod length of the probe rod, so as to reduce the influence of the length of the probe rod on the rod length correction coefficient calculated by the above method, so that the drop hammer in the dynamic probing equipment will not be affected by factors such as soil density and soil particle grading during the movement of the drop hammer in this high space.

[0060] In detail, Figure 3As shown, the support platform in this embodiment can be preferably a frame connecting rod structure 100, and an angle fixed connecting rod structure 200 connected to the frame structure 100 and used to support the ground at the other end. The dynamic probing equipment is arranged on the frame connecting rod structure 100, and the pendulum is perpendicular to the horizontal plane. The frame connecting rod structure is formed by multiple connecting rods connected in a frame-like manner.

[0061] As a preferred method, the frame connecting rod structure 100 in this embodiment includes a plurality of parallel arranged placement spaces for placing the dynamic probing equipment 300, and can facilitate the dynamic probing equipment to adjust its installation height, thereby flexibly adjusting its height for hammer testing.

[0062] Embodiment 2

[0063] This embodiment provides a method for testing the energy loss of dynamic penetration of a gravel pile. This embodiment is substantially the same as the first embodiment, except that: Figure 4 As shown, the detection platform in this embodiment is an above-water platform, and the dynamic probing equipment is carried on the detection platform to perform the initial test data and the secondary test data.

[0064] The detection platform follows the rise and fall of the tide, and at different rising positions of the tide, performs the preset hammering method on the gravel piles at the same reference position to obtain the initial test data and the secondary test data respectively, thereby realizing the test of gravel piles at different depths.

[0065] From the above content, it can be seen that the above method can make full use of the floating difference caused by the water level difference of the horizontal platform due to the tide, so that the drop hammer in the dynamic probing equipment will not be affected by factors such as soil density and soil particle grading during the high spatial movement of this floating difference. Therefore, during the test process, the overlying soil pressure in the gravel pile or the soil layer above it, the soil density, the soil particle grading and other factors on the rod length hammer coefficient and the hammer efficiency can be better reduced, so as to minimize the influence of other factors on the test results of the hammer efficiency, so as to better analyze the influence of the rod length on the number of dynamic probing hammer blows and the hammer efficiency, so as to more accurately calculate the rod length hammer coefficient, so as to improve the test accuracy and effectiveness of dynamic probing in the field of geotechnical in-situ testing.

[0066] In addition, by adopting the method of the water platform, there is no need to build a bracket, and a simple bracket 600 can be built on a ship, such as a drilling ship, and the dynamic sounding equipment is suspended on the water surface. The triangular simple bracket 600 for receiving the dynamic sounding equipment 300 is fixed to the hanging bracket 600 on the side of the ship, and a through hole 601 is provided on the hanging bracket 600 for passing the probe rod of the dynamic sounding equipment 300.

[0067] Further preferably, the hammer positions corresponding to the initial test data and the secondary test data have a tidal difference of at least 3m, so as to ensure that the drop hammer in the dynamic probing equipment is not affected by factors such as soil density and soil particle grading during the movement in the height space of the floating difference, i.e., the tidal difference, and to prevent the height of the height space from being too short to cause test errors.

[0068] Further preferably, the tidal difference is 15-25% of the rod length of the probe rod, so as to reduce the influence of the length of the probe rod on the rod length correction coefficient calculated by the above method, so that the drop hammer in the dynamic probing equipment will not be affected by factors such as soil density and soil particle grading during the process of high-altitude spatial movement.

[0069] In addition, it is worth mentioning that in this embodiment, the height distance between the suspension bracket 600 and the water surface is at least greater than or equal to 3 or 4 meters.

[0070] In addition, as a preferred embodiment, the above-water platform is a support platform disposed on a ship on the sea surface or a tidal river section.

[0071] Embodiment 3

[0072] This embodiment provides a method for testing the energy loss of dynamic penetration of a gravel pile. This embodiment is a further improvement of the first and second embodiments. The improvement is as follows: Figure 5 As shown, in this embodiment, further preferably, in step S40, according to a preset analysis method, the initial test data and the secondary test data are processed to calculate the rod length correction coefficient of the probe rod, and further includes:

[0073] Step S50, obtaining a first rod length correction coefficient and a second rod length correction coefficient, wherein the first rod length correction coefficient is obtained according to a land platform test, and the second rod length correction coefficient is obtained according to a water platform test;

[0074] Step S60: weighting the first rod length correction coefficient and the second rod length correction coefficient according to a preset weighting algorithm and weighting factor to obtain an initial rod length correction coefficient;

[0075] Step S70, calculating and obtaining the detection energy transfer efficiency data to be verified according to the initial rod length correction coefficient;

[0076] Step S80, comparing and analyzing the detection energy transfer efficiency data to be verified and the detection energy transfer efficiency data acquired in real time, and calculating the difference;

[0077] Step S90, determining whether the difference is within a preset error range;

[0078] Step S100: If yes, the initial rod length correction coefficient is used to determine the rod length correction coefficient.

[0079] Step S110, if not, then the weighting factor is corrected according to the preset correction factor, and the corrected rod length correction coefficient is obtained, and the above test is continued in a loop until the difference is within the error range, then the verification test is stopped, and the updating of the rod length correction coefficient is stopped; wherein the error range is only illustrated by taking the error rate of 5% as an example.

[0080] The above method can be used to correct and compensate the rod length correction coefficient obtained by preliminary calculation, thereby further reducing the error of the rod length correction coefficient and improving the accuracy of the results of the above-mentioned stone pile dynamic penetration energy loss test method.

[0081] For example, the initial value of the last weighting factor, such as ξ(i) = μ (i) *α1+(1-μ (i) )*α2,

[0082] ξ(1)=μ (1) *α1+(1-μ (1) )*α2,

[0083] ξ(2)=μ (2) *α1+(1-μ (2) )*α2, where μ (2)＝ 0.9*μ (1) .

[0084] ξ(3)=μ (3) *α1+(1-μ (3) )*α2, where μ (2)＝ 0.5*μ (1) .

[0085] …

[0086] ξ(i)=μ (i) *α1+(1-μ (i) )*α2.

[0087] Where ξ(1) is the initial rod length correction coefficient, μ1 is 0.5, α1 represents the first rod length correction coefficient, α2 represents the second rod length correction coefficient, and μ (i) represents the weighting factor, μ (i+1) =β * μ (i) , β is the correction factor, and its value can be preferably 0.9, μ (i+1)Represents the corrected weighting factor. Obviously, it should be noted that the rod length correction coefficient in this embodiment can also be preferably other values, which will not be described in detail here.

[0088] The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, certain details in the embodiments should not constitute a limitation of the present invention, and the scope of protection of the present invention shall be defined by the scope of the attached claims.

Claims

1. A method for testing the energy loss of dynamic penetration of a stone pile, characterized in that: include: Build a preset detection platform, and set a dynamic strain sensor and an acceleration sensor on the probe rod of the dynamic penetration equipment to be carried; Perform hammer tests on gravel piles using dynamic penetration equipment based on a preset hammering method and obtain initial test data; The dynamic penetration equipment is mounted on the detection platform, and then a hammer test is performed on the gravel pile based on the preset hammering method, and secondary test data is obtained. Secondly, the test data includes: dynamic strain data, acceleration data, and hammering number data; According to a preset analysis method, the initial test data and the secondary test data are processed to calculate the rod length correction coefficient of the probe rod.

2. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 1, characterized in that: The preset hammering method includes: within a preset depth, hammering is performed according to the position of a preset interval distance, and a set of test data obtained is recorded, and outside the preset depth, multiple hammering is performed according to the position of the interval distance, and the test data obtained by each hammering is recorded.

3. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 1, characterized in that: The preset depth is 20m and the distance is 1m.

4. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 1, characterized in that: According to a preset analysis method, the steps of processing the initial test data and the secondary test data to calculate the correction coefficient of the probe rod include: According to a preset speed and energy correlation algorithm, the initial test data and the secondary test data are calculated to obtain the initial detection energy transfer efficiency and the secondary detection energy transfer efficiency; The rod length correction coefficient is calculated according to the ratio of the primary detection energy transfer efficiency to the secondary detection energy transfer efficiency.

5. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 1, characterized in that: The rod length correction factor calculation formula is ETR1 / ETR2; Among them, ETR1 represents the energy transfer efficiency of the primary detection, and ETR2 represents the energy transfer efficiency of the secondary detection.

6. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 4, characterized in that: The velocity and energy correlation algorithm is the FV analysis method.

7. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 1, characterized in that: When the detection platform is an above-water platform, the detection platform follows the rise and fall of the tide, and at different rising positions of the tide, the preset hammering method is performed on the gravel piles at the same reference position to respectively obtain the initial test data and the secondary test data; wherein the above-water platform is a support platform set on a ship on the sea surface or a tidal river section.

8. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 7, characterized in that: Used to obtain the hammering positions corresponding to the initial test data and the secondary test data, the corresponding tidal difference is at least 3m; And / or, the tidal difference is 15-25% of the rod length of the probe rod.

9. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 1, characterized in that: When the detection platform is a support platform built on land, the height of the support platform and / or the depth of the foundation pit of the gravel pile are adjusted to thereby implement testing of gravel piles of different depths; And / or, the height between the dynamic penetration equipment on the detection platform and the gravel pile is 15-25% of the length of the probe rod.

10. The method for testing the energy loss of dynamic penetration of a stone pile according to claim 7, characterized in that: After the step of processing the initial test data and the secondary test data according to a preset analysis method to calculate the rod length correction coefficient of the probe rod, the method further includes: Obtaining a first rod length correction coefficient and a second rod length correction coefficient, wherein the first rod length correction coefficient is obtained according to a land platform test, and the second rod length correction coefficient is obtained according to a water platform test; According to a preset weighting algorithm and weighting factor, the first rod length correction coefficient and the second rod length correction coefficient are weighted to obtain an initial rod length correction coefficient; According to the initial rod length correction coefficient, the detection energy transfer efficiency data to be verified is calculated; Comparing and analyzing the detection energy transfer efficiency data to be verified and the detection energy transfer efficiency data acquired in real time, and calculating the difference; If the difference is not within the error range, the weighting factor is corrected according to the preset correction factor, and the corrected rod length correction coefficient is obtained, and the above test is continued in a loop until the difference is within the error range, then the verification test is stopped, and the updating of the rod length correction coefficient is stopped; If the difference is within the error range, the initial rod length correction factor is determined to be the rod length correction factor.

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