A Criteria for Determining the Stopping of Piling in Coral Reef Geology

Abstract

This invention discloses a method for determining the stopping criteria for driven piles in coral reef geology, comprising: pre-setting a matrix-structured pile location distribution; calculating the elevation change trend of each soil layer between two initially selected pile locations; constructing a three-dimensional geological map based on the pile location and soil layer elevation information; selecting several piles from the three-dimensional geological map slices as acceptance unit groups, with each row or column as the pile location; after the pile driving construction of each acceptance unit group is completed, calculating the hammering energy consumption of each pile in the acceptance unit group and selecting a benchmark pile; verifying the bearing capacity of the benchmark pile to see if it meets the requirements; if so, all piles in the acceptance unit meet the stopping criteria; otherwise, repeating steps 2-4 above. This invention, based on the bearing capacity verification of the benchmark pile to determine whether the remaining piles meet the stopping criteria, can greatly reduce the testing and acceptance costs, improve the efficiency of pile foundation construction and acceptance, save time, and significantly improve the overall construction efficiency of driven piles.

Description

Technical Field

[0001] This invention relates to the field of pile foundation construction stopping hammer judgment technology, specifically a standard judgment method for stopping hammer driving of driven piles applicable to coral reef geology. Background Technology

[0002] Currently, there are no quantitative calculation methods for pile foundation bearing capacity and penetration depth. In actual construction operations or design planning, qualitative regulations are generally used to determine the pile bearing capacity requirements. For example, the "Code for Construction of Wharf Structures" JTS215-2018 stipulates that the control standards for hammer-driven piles should be determined based on geological conditions, design bearing capacity, hammer type, pile type, and pile length, and should meet the following four requirements:

[0003] (1) When the bearing soil layer at the design pile tip is general cohesive soil, the design pile tip elevation should be used for control.

[0004] (2) When the bearing soil layer at the pile tip is gravel, dense sand or weathered rock, the penetration depth should be used for control. When the pile penetration depth has reached the control penetration depth but the pile tip has not reached the design elevation, the hammer should continue to penetrate 100mm or hammer for 30-50 blows. The average penetration depth should not be greater than the control penetration depth, and the distance between the pile tip and the design elevation should not exceed 1m-3m. When the elevation difference between the top surfaces of hard soil layers is not large, the smaller value should be taken. If the above provisions are exceeded, the design unit should be consulted for treatment.

[0005] (3) When the soil layer at the pile tip is stiff plastic cohesive soil or silty fine sand, the design pile tip elevation should be the primary control. If the pile tip does not reach the design elevation but the difference is not significant, the penetration depth can be used as the standard for stopping hammering. If the pile tip has reached the design elevation but the penetration depth is still greater than the control penetration depth, hammering should continue until the penetration depth approaches the control penetration depth. The depth of further sinking should take into account the influence of the construction water level. If necessary, the design unit should calculate and determine whether to stop hammering. If the pile tip has not reached the design elevation and the penetration depth is less than the control penetration depth, it can be handled according to section (2).

[0006] (4) When using a water jet hammer to drive piles, the standard for stopping the hammer should be controlled by the designed pile tip elevation. When the bearing stratum at the pile tip is weathered rock foundation, it should be controlled by the penetration depth.

[0007] Currently, many practical projects, including those not applied to wharf structures, refer to the above-mentioned stopping standard for hammering. However, this stopping standard under the construction specifications is not applicable to coral reef geological areas, mainly due to the unique characteristics of coral reef geology. The following problems arise when constructing driven piles in coral reef geological conditions:

[0008] a. The driving pile has low bearing capacity and easily penetrates coral sand and coral gravel soil. In highly weathered soft rocks such as coral reef limestone and phyllite, the penetration is much greater than that of conventional weathered rocks with the same SPT blow count. Often, when the foundation pile reaches the design elevation, the pile penetration is still much greater than the design control value, and it is doubtful whether the actual bearing capacity can meet the design requirements.

[0009] b. For the entire pile driving construction area, the penetration depth varies greatly after reaching the design elevation of the pile tip, making it difficult to determine a unified range to cover the driven piles in the entire construction area.

[0010] Therefore, for driving pile construction in coral reef geological areas, it is necessary to propose new standards for determining when to stop hammering, in order to guide and direct actual construction, save unnecessary construction steps and reduce the manpower and material resources consumed in construction, and provide a standard for stopping hammering while minimizing unnecessary hammering while meeting construction requirements. Summary of the Invention

[0011] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for determining the stopping criteria for driven piles in coral reef geology, which can solve the problems described in the background art.

[0012] The technical solution to achieve the purpose of this invention is: a method for judging the stopping criteria of driven piles in coral reef geology, comprising the following steps:

[0013] Step 1: Pre-determine the pile location distribution for the target coral reef geological area. One pile location corresponds to one pile foundation, and the pile location distribution is a matrix structure of rows and columns.

[0014] Step 2: The drilling locations should be arranged on the pile sites. Determine the soil layer distribution elevation for each drilling site. In each column or row of the pile site distribution, select at least two non-adjacent pile sites with drilling. The selected pile sites are the preliminary pile sites. Based on the soil layer elevations provided by the drilling at the preliminary pile sites, determine the corresponding elevations of each soil layer in each preliminary pile site.

[0015] Based on the elevation and elevation change rate of each soil layer at the initially selected pile locations, the elevation change trend of each soil layer at the remaining pile locations is calculated. The elevation change rate represents the change of the elevation of each soil layer with the pile spacing.

[0016] A three-dimensional geological map is constructed based on the elevation information of each soil layer at the location of each pile.

[0017] Step 3: Slice the 3D geological map, traverse each row or column by row or column, and select several piles with the same soil layer distribution, the same pile diameter, the same pile bottom elevation, and the same design bearing capacity requirements as the acceptance unit group for each row or column.

[0018] Step 4: Perform pile driving for each group of acceptance unit pile positions. After the pile driving is completed, calculate the hammer energy consumption of all piles in each group of acceptance unit pile positions to obtain the hammer energy consumption of each pile position in each group of acceptance units. Compare the pile bottom elevation and final hammer penetration of each pile in the corresponding group of acceptance unit pile positions, and select the benchmark pile representing the row or column of the acceptance unit pile position from each pile in the acceptance unit pile position.

[0019] Step 5: Verify the bearing capacity of the benchmark pile. If the bearing capacity of the benchmark pile meets the design bearing capacity requirements, then all other piles within the acceptance unit where the benchmark pile is located also meet the design bearing capacity requirements. In other words, all piles within the acceptance unit meet the hammer-stopping standard based on hammer energy consumption.

[0020] If the bearing capacity of the benchmark pile test does not meet the design requirements, then repeat steps 2-4 for the remaining pile positions that are not in the acceptance unit.

[0021] Furthermore, in step 1, the location of the boreholes for exploration and design is selected on the preset pile location.

[0022] Furthermore, the specific implementation of step 2 includes:

[0023] In each column of the pile location distribution, at least two non-adjacent pile locations with boreholes should be selected (Z). c,m Z c,n Alternatively, select at least two non-adjacent pile locations with boreholes in each row (Z). r,q Z r,w The pile positions selected based on the pile position column are recorded as the initial selection column pile positions, and the unselected pile positions are recorded as the non-initial selection column pile positions; the pile positions selected based on the pile position row are recorded as the initial selection row pile positions, and the unselected pile positions are recorded as the non-initial selection row pile positions. c,m Z represents the position of the m-th row in the current column. c,n Z represents the position of the nth row of the current column. r,q Z represents the stake position in the q-th column of the current row. r,w This indicates the position of the w-th column in the current row.

[0024] Boreholes were drilled to select initial pile locations. Soil layer elevation information was extracted from the boreholes to determine the elevation of each soil layer at each initial pile location. The initial pile locations include initial row pile locations and initial row pile locations. For each initial row pile location corresponding to the current row, the column elevation change rate of each soil layer corresponding to the initial row pile location group formed by any two closest initial row pile locations was calculated. The column soil layer elevation change rate represents the change in soil layer elevation with the pile spacing. Based on the column elevation change rate, the soil layer elevations of non-initial row pile locations within the corresponding initial row pile location group were calculated.

[0025] Alternatively, from the initial row pile positions corresponding to the current row, calculate the row elevation change rate of each soil layer corresponding to the initial row pile position group formed by any two closest initial row pile positions. The row pile foundation elevation change rate indicates the change of soil layer elevation with the pile spacing. Based on the row elevation change rate, calculate the soil layer elevation of each non-initial row pile position within the corresponding initial row pile position group.

[0026] Furthermore, in step 3, the piles are classified according to the pile diameter, pile wall thickness, design pile bottom elevation, design pile length, and preset pile bearing capacity requirements corresponding to the pile locations. Each row or column of piles is divided into corresponding types. Based on the type requirements, the piles in each row or column are sliced ​​from the three-dimensional geological map and selected as acceptance unit groups by selecting piles with the same soil layer distribution, the same design pile bottom elevation, the same pile diameter, and the same design bearing capacity requirements.

[0027] Furthermore, the specific implementation of step 4 includes the following steps:

[0028] Step 4-1: Calculate the hammering energy consumption according to the dynamic pile driving formula, which is shown below:

[0029]

[0030] In the formula, E d For hammering energy consumption, W h h is the weight of the pile hammer core. i The drop height of the pile hammer for each pile segment, s i The average penetration depth for each pile segment is used here, but only this value is taken to standardize the hammering energy consumption for each segment. N i The total number of hammer blows required for each pile segment, where n is the total number of pile segments.

[0031] Step 4-2: Summarize the hammer energy consumption E of all piles within the acceptance unit pile location. d The average penetration depth S of the final F-th strike F Actual pile bottom elevation D p ,in

[0032] 5) D of all piles p With respect to the design pile bottom elevation D s The difference should not exceed the preset value;

[0033] 6) Select the minimum hammer energy consumption E within the pile locations of each acceptance unit. d,min The corresponding pile is designated as the minimum hammer impact energy consumption pile;

[0034] 7) Select the maximum final hammer penetration depth S F，max The corresponding pile is designated as the pile with the maximum final hammer penetration.

[0035] 8) If the pile with the minimum hammer energy consumption and the pile with the maximum final hammer penetration are located at the same pile, then that pile is used as the reference pile; if they are not the same pile, then select E. d,min and S F,max The pile with a smaller ratio is used as the reference pile.

[0036] The beneficial effects of the present invention are as follows: The present invention has the following advantages:

[0037] 1. The penetration depth of driven piles in coral reef geology is large, which differs from conventional geotechnical engineering experience. In addition, the geological undulations are large, and the final hammer penetration depth varies greatly in different areas, making it difficult to determine a unified control value. It is difficult to propose a hammer-stopping standard for the entire construction area. The bearing capacity is uncertain and often requires large-area bearing capacity verification. However, a hammer-stopping standard based on hammer energy consumption, through acceptance unit grouping and selection of benchmark piles, can not only help ensure construction safety and quality, but also significantly improve construction efficiency.

[0038] 2. As a process quantity, the hammering energy consumption takes into account two pile driving construction parameters: pile penetration and hammering height. It can objectively reflect the difficulty of driving the pile into the soil. Compared with the traditional dual control principle of design pile tip elevation and final hammer penetration, it can realize the quantitative evaluation of the softness and hardness of the soil around the pile, and create conditions for comparing the strength of the soil around the pile with that of the pile.

[0039] 3. Coral reef geological driven piles have low bearing capacity and pose significant quality risks. Using high-strain testing to verify whether the bearing capacity meets the requirements for driving pile construction acceptance can ensure construction quality, promptly screen driven piles whose bearing capacity does not meet the design requirements, and address them in advance.

[0040] 4. By selecting a small number of benchmark piles from among many piles and verifying the structure based on the bearing capacity of the benchmark piles to determine whether the remaining piles meet the requirements for stopping the hammer, the testing cost can be greatly reduced, time can be saved, and the overall construction efficiency of the driven piles can be significantly improved. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the process of the present invention;

[0042] Figure 2 A schematic diagram showing the distribution of sampling piles for a specific coral reef geology.

[0043] Figure 3 A geological profile map of rows or columns obtained by slicing a three-dimensional geological schematic diagram according to a preset pile location distribution map;

[0044] Figure 4 This is a geological profile of a certain row of piles.

[0045] Figure 5 This is a schematic diagram of the actual pile location construction based on the benchmark pile. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0047] To address the aforementioned problems in driving pile construction in coral reef geological areas, the inventors, through practical work and research, discovered that for driving pile construction in coral reef geology, the primary focus should be on directly verifying whether the bearing capacity meets the requirements. Hammering energy consumption is introduced to evaluate the hardness of the soil surrounding the pile, allowing the pile with the softest surrounding soil to be selected as the benchmark pile. The bearing capacity test results of the benchmark pile represent other reference piles, thus ensuring that a batch of piles meets the requirements for stopping hammering. The standard-stipulated stopping hammering criteria often employ a dual control principle of design pile tip elevation and penetration depth. Penetration depth mainly depends on the hardness of the bearing soil layer and does not reflect the hardness of all soil layers surrounding the pile. Hammering energy consumption, however, applies to all soil layers surrounding the pile, taking into account the impact hammer's jump height and hammer core weight, providing a quantitative indicator for comparing the hardness of the soil surrounding piles with the same soil layer classification but varying thicknesses. Simultaneously, the design pile tip elevation and stopping hammering penetration depth parameters from commonly used stopping hammering criteria are also referenced for comparing the hardness of the bearing layer at the pile tip.

[0048] like Figures 1-5 As shown, a method for determining the stopping criteria for driven piles in coral reef geology includes the following steps:

[0049] Step 1: Pre-determine the pile location distribution for the target coral reef geological area. One pile location corresponds to one pile foundation, and the pile location distribution is a matrix structure of rows and columns.

[0050] In the pile location distribution, the column spacing between any two adjacent pile locations is the same, and the row spacing between any two pile locations is also equal. The survey and design borehole layout, which reflects the soil layer distribution information in the construction area, is also arranged at the pre-set pile locations.

[0051] refer to Figure 2 This is a schematic diagram showing the distribution of sampling piles for a specific coral reef. It consists of a matrix structure with seven rows (A-G) and eighty-six columns (1-86), totaling 602 pile positions, corresponding to the installation of 602 pile foundations. Some pre-arranged pile positions have boreholes. The column spacing between the pile positions in the first column of row A and the pile positions in the first column of row B is denoted as S. A1B1 The column spacing between the first column of row B and the first column of row C is denoted as S. B1C1 Then S A1B1 =S B1C1 Similarly, the column spacing between the pile positions in the first column of row A and the pile positions in the second column of row A is denoted as H. A1A2 The column spacing between the pile positions in the second column of row A and the pile positions in the third column of row A is denoted as H. A2A3 Then HA1A2 =H A2A3 Similarly, any two adjacent pile positions have the same column spacing and row spacing.

[0052] Figure 2 SG16, SG17, etc., represent borehole location numbers.

[0053] Step 2: In each column of the pile location distribution, select at least two non-adjacent pile locations with boreholes (Z). c,m Z c,n Alternatively, select at least two non-adjacent pile locations with boreholes in each row (Z). r,q Z r,w The pile positions selected based on the pile position column are recorded as the initial selection column pile positions, and the unselected pile positions, i.e., the remaining pile positions, are recorded as the non-initial selection column pile positions; the pile positions selected based on the pile position row are recorded as the initial selection row pile positions, and the unselected pile positions, i.e., the remaining pile positions, are recorded as the non-initial selection row pile positions. c,m This represents the position of the m-th row in the current column, corresponding to Z. c,n Z represents the position of the nth row in the current column; r,q This represents the q-th column position of the current row, corresponding to Z. r,w This indicates the position of the w-th column in the current row.

[0054] Based on the soil elevation information provided by the boreholes, the soil elevations corresponding to each preliminary pile position (including preliminary row pile positions and preliminary row pile positions) are determined. For each preliminary row pile position corresponding to the current row, the column elevation change rate of each soil layer corresponding to the preliminary row pile position group formed by any two closest preliminary row pile positions is calculated. The column elevation change rate represents the change of each soil layer elevation with the pile spacing of the pile foundation. Based on the column elevation change rate, the soil elevations of each non-preliminary row pile position within the corresponding preliminary row pile position group are calculated.

[0055] Similarly, from the initial row pile positions corresponding to the current row, the elevation change rate of each soil layer corresponding to the initial row pile position group formed by any two closest initial row pile positions can be calculated. The elevation change rate of each soil layer indicates the change of the elevation of each soil layer with the pile spacing of the pile foundation. Based on the elevation change rate, the elevation of each soil layer in the non-initial row pile positions within the corresponding initial row pile position group can be calculated.

[0056] Still referencing Figure 2Let's assume we calculate the distribution of soil layer elevations along each column. Taking the first column as the current column as an example, it has seven pile positions (rows A-G). Assuming the pile positions in rows A, D, and G are initially selected, the remaining four pile positions (rows B, C, E, and F) are not initially selected. First, determine the soil layer elevation P corresponding to the pile positions in row A. A The soil elevation P corresponding to the pile positions of row D D The soil layer elevation P corresponding to the pile position of row G. G Assuming a column spacing of 7.6m, then there are three column spacings from row A to row D, and also three column spacings from row D to row G. Therefore, the pile spacing from row A to row D and from row D to row G are both 3 * 7.6 = 22.8m. Thus, the soil layer elevation change rate (P_p) of the initial selected pile group formed by the piles in the first column of row A and the piles in the first column of row D is (P_p) D -P A ) / 22.8, assuming P A = -0.37m, P D = -7.04m, then the elevation change rate from row A to row D is [(-7.04)-(-0.37)] / 22.8 = -0.2925. Similarly, the elevation change rate from row D to row G is also -0.2925.

[0057] Among them, the non-preliminary selection pile positions within the preliminary selection pile position group formed by rows A and D are rows B and C. That is, corresponding to the current column (first column), rows B and C are located between rows A and D. Similarly, the non-preliminary selection pile positions within the preliminary selection pile position group formed by rows D and G are rows E and F.

[0058] Therefore, the soil layer elevation p corresponding to rows B and C is calculated based on the elevation change rate corresponding to the preliminary pile position group formed by rows A and D, and the soil layer elevation p corresponding to rows E and F is calculated based on the elevation change rate corresponding to the preliminary pile position group formed by rows D and G.

[0059] Therefore, the location of row B is -0.37 - 0.2925 * 7.6 = -2.593m, and the location of row C is -0.37 - 0.2925 * 7.6m * 2 = -4.816m. Similarly, the soil layer elevation p at the pile locations of rows E and F can also be calculated. By analogy, the soil layer elevations from A to G can be calculated for the remaining soil layers.

[0060] The elevations of the soil layers corresponding to other pile locations can also be calculated using this method.

[0061] Similarly, the elevation of each soil layer corresponding to each pile location can be calculated from the perspective of rows, thereby calculating the elevation of each soil layer corresponding to all pile locations in the pile location distribution. This will not be elaborated upon here.

[0062] Therefore, by calculating the soil layer elevations corresponding to each pile location, a three-dimensional geological diagram corresponding to the pile location distribution can be obtained, such as... Figure 3 As shown.

[0063] refer to Figure 3 , Figure 3 To construct a three-dimensional geological map based on the above method, a schematic diagram of soil layer elevations reflecting the entire coral reef geological area is presented. In an optional implementation, the coral reef geological area can be divided into different geological zones based on depth, typically including coral sand, completely weathered coral reef limestone, strongly weathered coral reef limestone, and moderately weathered coral reef limestone. Each pile location corresponds to different soil layer elevation information. In the above example, coral sand is used as an example. For instance, the top elevation of the coral sand layer at the location of pile A1 in row A is -0.37m, while the top elevations of the completely weathered coral reef limestone, strongly weathered coral reef limestone, and moderately weathered coral reef limestone layers are -25.67m, -32.67m, and -42.67m, respectively. Therefore, based on the three-dimensional geological map, the soil layer elevations of any pile at the preset pile location can be determined.

[0064] Therefore, by slicing the three-dimensional geological diagram according to the rows or columns of the preset pile location distribution map, a geological profile map of the row or column can be obtained, such as... Figure 3 As shown in the figure, the vertical axis represents the top elevation of each soil layer, and the horizontal axis (row number and column number) represents the column and row where the pile is located.

[0065] Step 3: After calculating the soil layer elevations corresponding to each pile location in Step 2, traverse each row or column by row or column. Classify the pile locations according to parameters such as pile diameter, pile wall thickness, design pile bottom elevation, design pile length, and preset (design) pile bearing capacity requirements. Divide each row or column into corresponding types. Based on these type requirements, select several pile locations in each row or column that share the same soil layer distribution, pile diameter, cross-sectional wall thickness, design pile bottom elevation, and preset (design) pile bearing capacity requirements as acceptance unit pile locations. For example, dividing by row to obtain acceptance unit pile locations, pile locations A1-A7 in row A (i.e., the pile locations in the first to seventh columns of row A, or the pile locations in row A corresponding to axis numbers 1-7) are the acceptance unit pile locations for row A. Similarly, the acceptance unit pile locations for row B are B1-B7, and so on. The acceptance unit pile locations for each row (or column) are the first seven pile locations.

[0066] The parameters of the acceptance unit pile locations for each row are categorized and referenced in the table below. The strata are referenced from the following profiles. Figure 3The corresponding sorting (rowing) slices are obtained as follows:

[0067]

[0068] Step 4: Perform pile driving for each group of acceptance unit pile positions. After the pile driving is completed, calculate the hammer energy consumption of all piles in each group of acceptance unit pile positions to obtain the hammer energy consumption of each pile in each group of acceptance unit pile positions. Based on the hammer energy consumption, pile bottom elevation and final hammer penetration, and in accordance with the principle that the difference in pile bottom elevation does not exceed 1m, the hammer energy consumption is taken as the minimum, and the final hammer penetration is taken as the maximum, select the benchmark pile representing the row or column of the acceptance unit pile position from each pile in the acceptance unit pile position.

[0069] Step 4 includes the following steps:

[0070] Step 4-1: Calculate the hammering energy consumption according to the dynamic pile driving formula. The dynamic pile driving formula is an existing calculation formula, as shown in the following formula:

[0071]

[0072] In the formula, E d For hammering energy consumption, W h h is the weight of the pile hammer core. i The drop height of the pile hammer for each pile segment, s i The average penetration depth for each pile segment is used here, but only this value is taken to standardize the hammering energy consumption for each segment. N i The total number of hammer blows required for each pile segment, where n is the total number of pile segments.

[0073] The table below is the pile driving record table for pile foundation A4 in the A-row acceptance unit. The table shows the hammer energy consumption of each pile segment during the pile driving process, calculated using the formula above:

[0074]

[0075]

[0076] In the table above, the hammering energy consumption of each pile segment is calculated and summed to obtain a total hammering energy consumption of 335038 kJ. This also means that the hammering energy consumption of pile A4 in the acceptance unit of row A is 335038 kJ. Following the method in step 4-1, the hammering energy consumption of the remaining piles A1, A2, A3, A5, A6, and A7 in the acceptance unit is calculated sequentially.

[0077] Step 4-2: Summarize the hammer energy consumption E of all piles within the acceptance unit pile location. d The average penetration of the final F-th strike (also known as the final hammer penetration) S F Actual pile bottom elevation Dp Where F is typically taken as 30, which is the average penetration of the last 30 blows; therefore, S F The value is generally taken as S. 30 More specifically,

[0078] 9) D of all piles p With respect to the design pile bottom elevation D s The difference should not exceed a preset value. The usual requirement is that D... p With D s The difference shall not exceed ±1.0m;

[0079] 10) Select the minimum hammer energy consumption E within the pile locations of each acceptance unit. d,min The corresponding pile is denoted as the pile with the minimum hammer impact energy consumption, which is E. d,min =min(E d,1 E d,2 , ..., E d,n The corresponding pile is ), and min means taking the minimum value.

[0080] 11) Select the maximum final hammer penetration value S F，max The corresponding pile is denoted as the pile with the maximum final hammer penetration, which is S. F,max =max(E d,1 E d,2 , ..., E d,n The corresponding stake is ), and max represents the maximum value.

[0081] 12) If the pile with the minimum hammer energy consumption and the pile with the maximum final hammer penetration are located at the same pile, then that pile is used as the reference pile; if they are not the same pile, then select E. d,min and S F,max The pile with a smaller ratio is used as the reference pile.

[0082] That is, choose E. d,min and S F,max The pile with the smaller ratio is used as the reference pile.

[0083] In special circumstances, if the hammer energy consumption of the pile with the minimum hammer energy consumption and the pile with the maximum final hammer penetration differ significantly, then both piles shall be selected as the benchmark piles.

[0084] Step 5: Verify the bearing capacity of the benchmark pile. The bearing capacity is verified using existing methods, such as the commonly used high-strain test method. If the bearing capacity of the benchmark pile meets the design bearing capacity requirements, then all other piles in the acceptance unit where the benchmark pile is located also meet the design bearing capacity requirements. In other words, all piles in the acceptance unit meet the hammer stopping standard based on hammer energy consumption.

[0085] If the bearing capacity of the benchmark pile test does not meet the design requirements, then repeat steps 2-4 for the remaining pile positions that are not in the acceptance unit.

[0086] Here's an example to illustrate the process described above. Figure 2 This diagram illustrates the pile layout of a certain engineering wharf area, which is located in a coral reef geological area.

[0087] Based on the pile foundation design information and pile location layout diagram provided in the survey and design calculation report, all piles to be constructed are classified. Then, according to the longitudinal row number, column number, pile diameter, wall thickness, design top elevation, design bottom elevation, design pile length, design bearing capacity requirements, and soil layer distribution obtained from the 3D geological map slices, the acceptance unit pile locations are divided, as shown in the table below:

[0088]

[0089]

[0090] Basic information on pile locations of acceptance unit C37-46

[0091] The hammer-stopping standard based on hammer impact energy consumption is used to verify the implementation of the acceptance units (C37-C53). The hammer impact energy consumption calculation for a single pile C40 is shown in Table 1 below, and the comparison of construction parameters between the benchmark pile and the reference pile in C37-C53 is shown in Table 2 below.

[0092]

[0093] Table 1

[0094]

[0095]

[0096] Table 2

[0097] As shown in Table 2, pile C40, which has the lowest hammer energy consumption and the highest final hammer penetration, is the "weak" pile among C37-C43 and is selected as the benchmark pile. The number of reference piles that the benchmark pile can represent is determined by comprehensively considering factors such as geological conditions and pile spacing. In this embodiment, the number of piles that the benchmark pile can represent is limited to three on each side. A high-strain test is performed on C40. If the bearing capacity of C40 meets the requirements, then the three piles C37, C38, and C39 on the left side of C40, and the three piles C41, C42, and C43 on the right side, can all meet the design bearing capacity requirements. Similarly, the "weak" pile C44 can be selected as the benchmark pile, representing the three piles C41, C42, and C43 on its left side, and the three piles C45, C46, ​​and C47 on its right side. The "weak" pile C50 can also be selected as the benchmark pile, representing the three piles C47, C48, and C49 on its left side, and the three piles C51, C52, and C53 on its right side.

[0098] refer to Figure 5 The implementation effect of this hammer-stopping control method in the engineering project of this embodiment is that the bearing capacity verification results of 174 piles were used to determine that all 174 piles met the hammer-stopping standard, which greatly reduced the testing cost and time cost and significantly improved the construction efficiency.

[0099] Compared with existing methods for determining whether a hammer can stop, this invention has the following advantages:

[0100] 1. The penetration depth of driven piles in coral reef geology is large, which differs from conventional geotechnical engineering experience. In addition, the geological undulations are large, and the final hammer penetration depth varies greatly in different areas, making it difficult to determine a unified control value. It is difficult to propose a hammer-stopping standard for the entire construction area. The bearing capacity is uncertain and often requires large-area bearing capacity verification. However, a hammer-stopping standard based on hammer energy consumption, through acceptance unit grouping and selection of benchmark piles, can not only help ensure construction safety and quality, but also significantly improve construction efficiency.

[0101] 2. As a process quantity, the hammering energy consumption takes into account two pile driving construction parameters: pile penetration and hammering height. It can objectively reflect the difficulty of driving the pile into the soil. Compared with the traditional dual control principle of design pile tip elevation and final hammer penetration, it can realize the quantitative evaluation of the softness and hardness of the soil around the pile, and create conditions for comparing the strength of the soil around the pile with that of the pile.

[0102] 3. Coral reef geological driven piles have low bearing capacity and pose significant quality risks. Using high-strain testing to verify whether the bearing capacity meets the requirements for driving pile construction acceptance can ensure construction quality, promptly screen driven piles whose bearing capacity does not meet the design requirements, and address them in advance.

[0103] 4. By selecting a small number of benchmark piles from among many piles and verifying the structure based on the bearing capacity of the benchmark piles to determine whether the remaining piles meet the requirements for stopping the hammer, the testing cost can be greatly reduced, time can be saved, and the overall construction efficiency of the driven piles can be significantly improved.

[0104] The embodiments disclosed in this specification are merely illustrative of one aspect of the invention, and the scope of protection of the invention is not limited to these embodiments. Any other functionally equivalent embodiments fall within the scope of protection of the invention. Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the scope of protection of the claims of this invention.

Claims

1. A method for judging a standard of a hammer stop for a driven pile suitable for a coral reef geology, characterized by, The method comprises the following steps: Step 1: presetting pile position distribution on the target coral reef geological area, one pile position corresponding to one pile foundation, and the pile position distribution being in a matrix structure of row and column distribution; Step 2: surveying and designing the drilling position to be arranged on the pile position, determining the soil layer distribution elevation of each drilling hole, selecting at least two non-adjacent pile positions with drilling holes in each column or at least two non-adjacent pile positions with drilling holes in each row in the pile position distribution, the selected pile positions being preliminary selected pile positions, determining the elevations of each soil layer corresponding to each preliminary selected pile position according to the soil layer elevations provided by the drilling holes arranged in the preliminary selected pile positions, calculating the elevation change trend of each soil layer of the remaining pile positions according to the soil layer elevations of the preliminary selected pile positions and the elevation change rate, and the elevation change rate representing the change of the soil layer elevation with the pile spacing; constructing a three-dimensional geological map according to the elevation information of each soil layer at the position of each pile; Step 3: slicing the three-dimensional geological map, traversing each row or each column, and selecting several pile positions with the same soil layer distribution, the same pile diameter, the same pile bottom elevation and the same design bearing capacity requirement in each row or each column as an acceptance unit group; Step 4: performing pile driving construction for each group of acceptance unit pile positions, calculating the hammering energy consumption of all piles of each group of acceptance unit pile positions after the pile driving construction is completed, obtaining the hammering energy consumption corresponding to each pile position of each group of acceptance unit, and comparing the pile bottom elevations and final hammer penetration of each pile in the corresponding group of acceptance unit pile positions to select a reference pile from each pile in the acceptance unit pile position, the reference pile representing the row or column of the group of acceptance unit pile positions; Step 5: verifying the bearing capacity of the reference pile, if the bearing capacity of the reference pile meets the design bearing capacity requirement, the remaining pile positions in the acceptance unit pile position of the reference pile all meet the design bearing capacity requirement, that is, all the piles in the acceptance unit meet the stop hammering standard based on the hammering energy consumption, if the bearing capacity of the reference pile does not meet the design requirement, repeating steps 2-4 for the remaining pile positions not in the acceptance unit pile position.

2. The method for judging the standard of a driving pile stop hammer suitable for a coral reef geology according to claim 1, characterized in that, In step 1, the surveying and designing position of the drilling hole is selected on the preset pile position.

3. The method for judging the standard of a driving pile stop hammer suitable for a coral reef geology according to claim 1, characterized in that, The specific implementation of step 2 comprises: At least two non-adjacent pile sites (Z c,m , Z c,n ) arranged with drill holes are selected in each column of pile site distribution, or at least two non-adjacent pile sites (Z r,q , Z r,w ) arranged with drill holes are selected in each row of pile site distribution. The pile sites selected according to the pile site column are denoted as primary column pile sites, and the pile sites not selected are denoted as non-primary column pile sites. The pile sites selected according to the pile site row are denoted as primary row pile sites, and the pile sites not selected are denoted as non-primary row pile sites. Z c,m represents the pile site of the mth row of the current column, Z c,n represents the pile site of the nth row of the current column, Z r,q represents the pile site of the qth column of the current row, and Z r,w represents the pile site of the wth column of the current row. The preliminary selected pile positions are provided with drilling holes, the soil layer elevation information is extracted according to the drilling holes, the soil layer elevations of each preliminary selected pile position are determined, the preliminary selected pile positions include preliminary selected column pile positions and preliminary selected row pile positions, for each preliminary selected column pile position corresponding to the current column, the column elevation change rate of each soil layer corresponding to the preliminary selected column pile position group formed by any two closest preliminary selected column pile positions is calculated, the column soil layer elevation change rate representing the change of the soil layer elevation with the pile spacing of the pile foundation, and the soil layer elevations of the non-preliminary selected column pile positions within the corresponding preliminary selected column pile position group are calculated according to the column elevation change rate, or from each preliminary selected row pile position corresponding to the current row, the row elevation change rate of each soil layer corresponding to the preliminary selected row pile position group formed by any two closest preliminary selected row pile positions is calculated, the row pile foundation elevation change rate representing the change of the soil layer elevation with the pile spacing of the pile foundation, and the soil layer elevations of the non-preliminary selected row pile positions within the corresponding preliminary selected row pile position group are calculated according to the row elevation change rate.

4. The method for judging the standard of a driving pile stop hammer suitable for a coral reef geology according to claim 1, characterized in that, In step 3, according to the pile diameter, the wall thickness of the pile foundation, the design pile bottom elevation, the design pile length and the preset pile foundation bearing capacity requirement corresponding to the pile position, the corresponding type is classified for each row or each column of the pile position, and according to the type requirement, a plurality of piles containing the same soil layer distribution, the same design pile bottom elevation, the same pile diameter and the same design bearing capacity requirement are selected as an acceptance unit group from the three-dimensional geological map according to each row or each column of the pile position.

5. The method for judging the standard of a driving pile stop hammer suitable for a coral reef geology according to claim 1, characterized in that, The specific implementation of step 4 includes the following steps: Step 4-1: Calculate the hammer energy consumption according to the dynamic pile sinking formula, and the dynamic pile sinking formula is as follows: where E d is the hammer energy consumption, W h is the weight of the hammer core, h i is the drop height of the hammer for each pile driving segment, s i is the average penetration value for each pile driving segment, here only its value is taken to normalize the hammer energy consumption for each segment, N i is the total number of hammer blows required for each pile driving segment, n is the total number of pile driving segments, Step 4-2: Sum up the hammer energy consumption E of all piles in the pile site of the acceptance unit d , the average value S of the last F blows F , the actual pile bottom elevation D p wherein 1) D of all piles p The difference between the designed pile bottom elevation D s and the actual pile bottom elevation D is not more than a preset value; 2) Select the minimum hammer energy consumption E in each group of acceptance unit pile position d,min The pile corresponding to the minimum hammer energy consumption is recorded as the minimum hammer energy consumption pile; 3) Select the maximum value of the final hammer penetration S F，max the pile corresponding to the maximum value of the final hammer penetration S is noted as the pile with the maximum final hammer penetration; 4) If the minimum hammer energy consumption pile and the maximum final hammer penetration pile are the same pile, the pile is taken as the reference pile; if not, select E d,min and S F,max with the smaller ratio of S / E as the reference pile.

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