Safety evaluation method for blasting vibration of pile foundation structure

Abstract

The present invention belongs to the field of blasting technology and relates to a method for evaluating the blasting vibration safety of pile foundation structures. The method comprises the following steps: 1) obtaining pile foundation structure parameter information; 2) constructing a finite element model; 3) setting single blasting conditions and performing calculations on the finite element model; 4) identifying vulnerable points and monitoring points of the pile foundation structure due to blasting vibration; 5) setting multiple blasting conditions and performing calculations on the finite element model; 6) fitting the results of multiple blasting simulations; and 7) evaluating the blasting vibration safety of the pile foundation structure. The present invention provides a method for evaluating the blasting vibration safety of pile foundation structures that can provide a scientific basis for blasting vibration safety assessment, assist in determining blasting construction plans, and ensure the quality and safety of the blasting construction process.

Description

Technical Field

[0001] The invention belongs to the technical field of blasting, and relates to a blasting safety evaluation method, in particular to a blasting vibration safety evaluation method for a pile foundation structure. Background Art

[0002] In recent years, with urban development, urban blasting activities have increased, including excavation of foundation pits, subway tunnels, and demolition of structures. Assessing the harmful effects of blasting vibration on adjacent buildings is crucial for ensuring the safety of life and property and the on-time delivery of engineering projects. Current safety assessments for blasting of urban buildings rely solely on the safe allowable particle vibration velocities recommended in the "Safety Regulations for Blasting (GB6722-2014)." The reference values ​​proposed in this standard are empirical and general, failing to provide flexible criteria for determining the specific characteristics of the project. Furthermore, this standard does not clearly define the safe allowable vibration velocities for blasting of pile-based structures, such as viaducts and civil buildings, and lacks a method for assessing the safe charge and safe blasting distance for blasting adjacent pile-based structures. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems existing in the background technology, the present invention provides a pile foundation structure blasting vibration safety evaluation method which can provide a scientific basis for the pile foundation structure blasting vibration safety evaluation, help determine the blasting construction plan, and ensure the quality and safety of the blasting construction process.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A pile foundation structure blasting vibration safety assessment method, characterized in that the pile foundation structure blasting vibration safety assessment method comprises the following steps:

[0006] 1) Obtaining pile foundation structure parameter information;

[0007] 2) constructing a finite element model based on the pile foundation structure parameter information obtained in step 1);

[0008] 3) setting a single blasting condition, and calculating the finite element model constructed in step 2) based on the single blasting condition to obtain a single blasting simulation result;

[0009] 4) confirming the blasting vibration-vulnerable points and monitoring points of the pile foundation structure based on the single blasting simulation results obtained in step 3);

[0010] 5) setting multiple blasting conditions, and calculating the finite element model constructed in step 2) based on the multiple blasting conditions to obtain multiple blasting simulation results; the multiple blasting simulation results include the maximum tensile stress of the vulnerable point and the maximum vibration velocity of the monitoring point under different charge amounts and different blasting distances;

[0011] 6) performing fitting based on the multiple blasting simulation results obtained in step 5) to obtain fitting results;

[0012] 7) Evaluate the blasting vibration safety of the pile foundation structure based on the pile foundation structure parameter information obtained in step 1) and the fitting result obtained in step 6).

[0013] Preferably, the pile foundation structure parameter information in step 1) adopted by the present invention includes pile foundation material parameters, rock and soil material parameters and pile foundation geometry information; the pile foundation material parameters include density, elastic modulus, Poisson's ratio and tensile strength of concrete.

[0014] Preferably, the specific implementation of step 2) adopted by the present invention is:

[0015] 2.1) The concrete and rock-soil mass were modeled using Solid164 solid elements to obtain a concrete rock-soil model;

[0016] 2.2) Model the steel bar using Beam161 beam elements to obtain a steel bar model;

[0017] 2.3) connecting the concrete rock and soil model obtained in step 2.1) and the steel bar model obtained in step 2.2) using a common node method;

[0018] 2.4) Divide the explosives and air into a multi-material ALE grid, and divide the rest into a Lagrangian grid. Then couple the ALE grid and the Lagrangian grid using the fluid-structure coupling keyword.

[0019] 2.5) Set the surrounding and bottom of the rock mass as non-reflecting boundary conditions;

[0020] 2.6) Set the top of the pile foundation as a fixed constraint and obtain the finite element model.

[0021] Preferably, the single blasting condition in step 3) adopted in the present invention is a charge amount and a blasting distance that simulates actual blasting conditions; the single blasting simulation result includes a first stress distribution and a second stress distribution; the first stress distribution is a curve of the relationship between the maximum tensile stress of the pile foundation structure unit and the depth of the pile foundation structure unit; the pile foundation structure unit is a unit grid obtained by dividing the finite element model; the second stress distribution is a curve of the relationship between the maximum tensile stress of the unit on the cross section of the top of the pile foundation structure and the azimuth angle of the top of the pile foundation structure.

[0022] Preferably, the vulnerable point in step 4) adopted in the present invention is located at the depth corresponding to the maximum value of the first stress distribution and the azimuth corresponding to the maximum value of the second stress distribution; the monitoring point is a unit in the finite element model that is the same as the vibration sensor point at the actual blasting construction site.

[0023] Preferably, the multiple blasting conditions in step 5) adopted in the present invention are to simulate different charge amounts and different blasting distances that conform to actual blasting conditions.

[0024] Preferably, the specific implementation of step 6) adopted by the present invention is:

[0025] 6.1) Using the least squares method, a linear fit is performed on the maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charge loads and different explosion distances to obtain a first relationship. The expression of the first relationship is v = a × σ + b; where v is the maximum vibration velocity at the monitoring point, σ is the maximum tensile stress at the vulnerable point, and a and b are both undetermined coefficients;

[0026] 6.2) The least squares method is used to perform multivariate nonlinear fitting on the maximum vibration velocity of the monitoring point under different charge amounts and different explosion distances and the corresponding charge amounts and explosion distances to obtain the second relationship. The expression of the second relationship is v = c × Q A R B ; Among them, v is the maximum vibration velocity at the monitoring point, Q is the charge amount, R is the explosion distance, and c, A, and B are all unknown coefficients.

[0027] Preferably, the specific implementation of step 7) adopted by the present invention is:

[0028] 7.1) Substitute the tensile strength of the pile foundation material parameters as the maximum tensile stress into the first equation to calculate the safe allowable vibration velocity at the monitoring point. Compare the safe allowable vibration velocity at the monitoring point with the output value of the vibration sensor at the actual blasting construction site. If the output value of the vibration sensor is greater than the safe allowable vibration velocity at the monitoring point, the pile foundation structure is considered to be in an unsafe state; otherwise, the pile foundation structure is considered to be in a safe state.

[0029] 7.2) Substituting the safe allowable vibration velocity at the monitoring point as the maximum vibration velocity at the monitoring point into the second equation, the safety evaluation basis for blasting vibration of the pile foundation structure is calculated. The safety evaluation basis for blasting vibration of the pile foundation structure is the safe blasting distance under a certain charge amount or the safe charge amount under a certain blasting distance.

[0030] A pile foundation structure blasting vibration safety evaluation system for implementing the pile foundation structure blasting vibration safety evaluation method as described above is characterized in that the pile foundation structure blasting vibration safety evaluation system includes:

[0031] A modeling unit for obtaining pile foundation structure parameter information and constructing a finite element model based on the pile foundation structure parameter information;

[0032] A simulation unit for performing a single simulation blast or multiple simulation blasts on a finite element model;

[0033] Fixed-point unit used to identify vulnerable points and monitoring points of pile foundation structures caused by blasting vibration;

[0034] A fitting unit for fitting multiple blasting simulation results;

[0035] An evaluation unit for evaluating the blasting vibration safety of the pile foundation structure based on the fitting results and pile foundation structure parameter information;

[0036] A calculation unit for calculating a finite element model and for calculating a safe explosion distance under a certain charge or a safe charge under a certain explosion distance.

[0037] Preferably, the modeling unit used in the present invention includes:

[0038] A component modeling unit, wherein the component modeling unit is used to model the concrete and rock soil using Solid164 entity elements and to model the steel bars using Beam161 beam elements;

[0039] A connection unit, wherein the connection unit is used to connect concrete and steel bars using a common node method;

[0040] A partitioning unit, wherein the partitioning unit is used to partition the explosive and air into a multi-material ALE grid, and to partition the remaining part into a Lagrangian grid, and to couple the ALE grid and the Lagrangian grid through a fluid-structure coupling keyword;

[0041] A boundary setting unit, wherein the boundary setting unit is used to set the periphery and bottom of the rock and soil body as non-reflecting boundary conditions; and set the top of the pile foundation as a fixed constraint;

[0042] Preferably, the simulation unit includes a single simulation unit and a multiple simulation unit;

[0043] The single simulation unit includes:

[0044] A single charge simulation unit for simulating a charge that meets actual blasting conditions;

[0045] A single blast distance simulation unit for simulating a blast distance that conforms to actual blasting conditions;

[0046] A first output unit for obtaining a single blasting simulation result;

[0047] The multiple simulation unit includes:

[0048] A multiple charge simulation unit for simulating different charge amounts by changing the number of rolls;

[0049] A multiple explosion distance simulation unit for obtaining different explosion distances by changing the horizontal distance from the center of the explosive to the pile foundation structure;

[0050] A second result output unit for obtaining multiple blasting simulation results.

[0051] The beneficial effects of the present invention are:

[0052] The present invention provides a method for evaluating the blasting vibration safety of a pile foundation structure, comprising: 1) acquiring pile foundation structure parameter information; 2) constructing a finite element model based on the pile foundation structure parameter information obtained in step 1); 3) setting a single blasting condition, and calculating the finite element model constructed in step 2) based on the single blasting condition to obtain a single blasting simulation result; 4) confirming a blasting vibration-vulnerable point and a monitoring point of the pile foundation structure based on the single blasting simulation result obtained in step 3); 5) setting multiple blasting conditions, and calculating the finite element model constructed in step 2) based on the multiple blasting conditions to obtain multiple blasting simulation results; the multiple blasting simulation results include maximum tensile stresses of vulnerable points and maximum vibration velocities of monitoring points under different charge amounts and different blasting distances; 6) performing fitting according to the multiple blasting simulation results obtained in step 5) to obtain fitting results; and 7) evaluating the blasting vibration safety of the pile foundation structure based on the pile foundation structure parameter information obtained in step 1) and the fitting results obtained in step 6). The present invention simulates, analyzes, and calculates the vulnerable points of the pile foundation structure after blasting, the relationship between the maximum tensile stress at the vulnerable points and the maximum vibration velocity at the monitoring points, and the relationship between the maximum vibration velocity at the monitoring points and the charge amount and blasting distance. Combining the pile foundation structure parameter information and the above relationships, the safe allowable vibration velocity at the monitoring points, as well as the safe charge amount and safe blasting distance for on-site blasting construction, can be obtained. The output value of the vibration sensor at the on-site monitoring point is compared with the safe allowable vibration velocity at the monitoring point to achieve a safety assessment of the pile foundation structure blasting. The present invention not only provides a scientific basis for the safety assessment of pile foundation structure blasting vibration, but also helps determine the blasting construction plan and ensure the quality and safety of the blasting construction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of the pile foundation structure blasting vibration safety evaluation method provided by the present invention;

[0054] Figure 2 is a curve showing the relationship between the maximum tensile stress of the pile foundation structure unit used in the present invention and the depth of the unit;

[0055] Figure 3 It is a curve showing the relationship between the maximum tensile stress of a unit and the azimuth angle of the unit on the top cross section of the pile foundation structure adopted by the present invention;

[0056] Figure 4 is the horizontal relative position of the blasthole, monitoring point and pile foundation used in the present invention;

[0057] Figure 5 It is the fitting result of the maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point adopted by the present invention;

[0058] Figure 6 It is the fitting result of the maximum vibration velocity of the monitoring point and the corresponding charge amount and explosion distance adopted by the present invention;

[0059] Figure 7 It is a structural schematic diagram of the pile foundation structure blasting vibration safety evaluation system of the present invention;

[0060] Markings in the figure:

[0061] 1-Blast hole No. 1; 2-Blast hole No. 2; 3-Blast hole No. 3; 4-Blast hole No. 4; 5-Blast hole No. 5; 6-Pile foundation; 7-Monitoring point; 100-Blasting vibration safety assessment system; 110-Modeling unit; 120-Single simulation unit; 130-Fixed-point unit; 140-Multiple simulation unit; 150-First fitting unit; 160-Second fitting unit; 170-Evaluation unit; 180-Calculation unit. DETAILED DESCRIPTION

[0062] Example 1:

[0063] like Figure 1 As shown, this embodiment provides a method for evaluating the safety of pile foundation structure blasting vibration, including:

[0064] S1. Obtaining pile foundation structure parameter information and constructing a finite element model based on the pile foundation structure parameter information. It should be noted that the parameter information includes material parameters and geometric information of concrete, steel bars, and rock and soil.

[0065] In some specific embodiments, step S1 specifically includes:

[0066] S11. Model the concrete and rock-soil using Solid164 entity elements;

[0067] S12, model the steel bars using Beam161 beam elements;

[0068] S13. Set the concrete and steel bars to be connected using the common node method;

[0069] S14, divide the explosives and air into multi-material ALE grids, divide the rest into Lagrangian grids, and couple the ALE grid and Lagrangian grid using the fluid-structure coupling keyword;

[0070] S15. Set the surrounding areas and bottom of the rock and soil body as non-reflecting boundary conditions;

[0071] S16. Set the top of the pile foundation as a fixed constraint.

[0072] In some specific embodiments, step S1 further includes:

[0073] The explosives were simulated using the MAT-HIGH-EXPLOSIVE-BURN material model, and the EOS_JWL equation of state was used to calculate the pressure during blasting simulation. By adopting the high-energy explosive material model (MAT-HIGH-EXPLOSIVE-BURN) combined with the EOS_JWL equation of state that describes the pressure-volume relationship of the explosive gas, the explosives can describe in detail the combustion and explosion process of the explosives, as well as the force exerted by the high-pressure gas generated by the explosion on the cladding and surrounding medium, thereby providing more accurate simulation results.

[0074] The air was simulated using the MAT-NULL material model, and the EOS-LINEAR-POLYNOMIAL equation of state was used to calculate the pressure during the blast simulation. The linear polynomial equation of state can simulate the ideal gas equation of state by setting relevant constants, including the gas pressure, polytropic index, current and initial density, and energy density, thereby providing an accurate mathematical description of the gas dynamics. It has significant advantages in describing the performance of the high-pressure area of ​​blast pressure, while also ensuring good consistency with experimental data, thereby improving the predictive ability and reliability of the model.

[0075] The steel bars were simulated using the MAT-PLASTIC-KINEMATIC plastic flow model. The MAT-PLASTIC-KINEMATIC plastic flow model is suitable for simulating isotropic nonlinear hardening materials and can accurately capture the plastic deformation behavior of steel under high-speed loading, such as blasting.

[0076] The rock and soil are simulated using the MAT-MOHR-COULOMB material model; the concrete is simulated using the RHT model; the RHT model introduces three limit surfaces: elastic limit surface, failure surface, and residual strength surface, which can describe the variation law of the initial yield strength, failure strength, and residual strength of concrete.

[0077] S2. Simulate and calculate a finite element model under a charge amount and a blasting distance to obtain a single blasting simulation result, wherein the single blasting simulation result includes a first stress distribution and a second stress distribution. The first stress distribution is a curve showing the relationship between the maximum tensile stress of a pile foundation structure unit and the depth of the unit, and the second stress distribution is a curve showing the relationship between the maximum tensile stress of a unit on the top cross section of the pile foundation structure and the azimuth angle of the unit. In some specific embodiments, step S2 specifically includes:

[0078] S21 simulates a charge that conforms to actual blasting conditions;

[0079] S22 simulates a blasting distance that conforms to actual blasting conditions;

[0080] S23 obtains the results of a single blasting simulation, including a curve showing the relationship between the maximum tensile stress of a pile foundation structure unit and the depth of the unit, and a curve showing the relationship between the maximum tensile stress of a unit on the top cross section of the pile foundation structure and the azimuth angle of the unit.

[0081] In this embodiment, a charge of 4kg and a blasting distance of 40m are preset. The relationship curve between the maximum tensile stress of the unit on one side of the pile foundation structure and the pile foundation depth is as follows: Figure 2 As shown in the figure, the relationship curve between the maximum tensile stress of the unit on the top cross section of the pile foundation structure and the azimuth angle of the unit is as follows: Figure 3 shown.

[0082] S3. Based on the relationship curves between the maximum tensile stress of a unit and the depth of the pile foundation, and the relationship curves between the maximum tensile stress of a unit and the azimuth angle of the unit, it can be determined that the vulnerable point to blasting vibration of the pile foundation is located on the back-blast side of the pile top. In this embodiment, a vibration sensor is deployed at a preset on-site blasting monitoring point located 50 cm from the back-blast side of the pile top.

[0083] S4. Simulate and calculate the finite element model under different charge amounts and different blasting distances to obtain multiple blasting simulation results. The multiple blasting simulation results include the maximum tensile stress of the vulnerable point and the maximum vibration velocity of the monitoring point under different charge amounts and different blasting distances.

[0084] In this embodiment, different charge weights are preset to be 4 kg, 6 kg, 8 kg, 10 kg, and 12 kg, and different blasting distances between the explosives and the pile foundation are 20 m, 30 m, 40 m, 50 m, and 60 m, respectively. The monitoring point is located 50 cm from the back blast side of the top of the pile foundation. The relative position relationship between the blasthole, the monitoring point, and the pile foundation is as follows: Figure 4 The maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charge amounts and different explosion distances of this embodiment are shown in Table 1.

[0085] Table 1

[0086]

[0087]

[0088] S5. Fit the maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charge amounts and different explosion distances to obtain the first relationship.

[0089] The maximum tensile stress of the vulnerable point and the maximum vibration velocity of the monitoring point in Table 1 are fitted, and the fitting results are as follows: Figure 5 As shown in the figure, σ represents the maximum tensile stress at the vulnerable point, and v represents the maximum vibration velocity at the monitoring point. The first relationship is:

[0090] v = 0.98 × σ - 0.095;

[0091] S6. Fit the maximum vibration velocity at the monitoring point and the corresponding charge amount and explosion distance to obtain the second relationship.

[0092] The maximum vibration velocity, charge amount and explosion distance of the monitoring point in Table 1 are fitted, and the fitting results are as follows: Figure 6 As shown in the figure, R represents the explosion distance, Q represents the charge amount, and the second relationship is:

[0093] v=112.2×Q 0.7 ×R -1.67 ;

[0094] S7. According to the pile foundation structure parameter information and the first relationship, the safe allowable vibration velocity of the monitoring point is obtained, and the safety evaluation of the pile foundation structure is obtained by comparing the output value of the vibration sensor at the actual blasting construction site.

[0095] In this embodiment, the pile foundation structure concrete uses C30 concrete, and the design tensile strength value is 1.43 MPa. Substituting this value into the first relationship, the safe allowable vibration velocity at the monitoring point is 1.3 cm / s. This value is compared with the output value of the vibration sensor at the actual blasting construction site to obtain the pile foundation structure safety evaluation, which specifically includes:

[0096] When the output value of the vibration sensor is less than 1.3cm / s, the pile foundation structure is safe;

[0097] When the output value of the vibration sensor is greater than 1.3 cm / s, the pile foundation structure is damaged;

[0098] S8. Calculate the safe explosion distance under a certain charge amount or the safe charge amount under a certain explosion distance based on the safe allowable vibration velocity of the monitoring point and the second relationship.

[0099] In this embodiment, the safe allowable vibration velocity of 1.3 cm / s at the monitoring point is substituted into the second relational equation to obtain:

[0100] Q = 1.71 × 10 -3 ×R 2.39 , the corresponding safe charge amount can be obtained by substituting the blasting distance of the actual blasting construction site into the formula. For blasting distances of 20m, 30m, 40m, 50m, and 60m, the calculated safe charge amounts are 2.2kg, 5.8kg, 11.5kg, 19.7kg, and 30.4kg respectively;

[0101] Or R = 14.4 × Q 0.42 Substituting the actual charge amount at the blasting construction site into the formula can obtain the corresponding safe blasting distance. For charge amounts of 4kg, 6kg, 8kg, 10kg, and 12kg, the calculated safe blasting distances are 25.8m, 30.6m, 34.5m, 37.9m, and 40.9m respectively.

[0102] This embodiment can simulate the blasting effect in actual construction more accurately through the simulation of the finite element model, and then accurately evaluate the safety of the pile foundation structure at different blasting distances and different charges. By establishing a relationship between the charge, blasting distance, maximum tensile stress at the vulnerable point and maximum vibration velocity at the monitoring point, the safety evaluation of the pile foundation structure is made more scientific and reasonable. This application not only has guiding significance for the current safety evaluation of pile foundation structure blasting vibration, but also can provide a reference for similar projects in the future, especially in terms of preventing and treating the safety of pile foundation structures caused by blasting. The data and experience accumulated through the research of this method can provide a scientific basis for the safe construction of pile foundation structures near blasting.

[0103] Example 2:

[0104] like Figure 7 As shown, this embodiment provides a pile foundation structure blasting vibration safety assessment system 100. Corresponding to the pile foundation structure blasting vibration safety assessment method in the embodiment, the safety assessment system 100 includes:

[0105] The modeling unit 110 is used to obtain pile foundation structure parameter information and construct a finite element model according to the pile foundation structure parameter information;

[0106] The single simulation unit 120 is used to simulate and calculate the finite element model under a certain charge amount and a certain blasting distance to obtain a single blasting simulation result. The single blasting simulation result includes a first stress distribution and a second stress distribution. The first stress distribution is a curve showing the relationship between the maximum tensile stress of the pile foundation structure unit and the depth of the unit. The second stress distribution is a curve showing the relationship between the maximum tensile stress of the unit on the top cross section of the pile foundation structure and the azimuth angle of the unit.

[0107] Fixed-point unit 130, used to identify the vulnerable points and monitoring points of the pile foundation structure due to blasting vibration. The vulnerable points are located at the depth corresponding to the maximum value of the first stress distribution and the azimuth corresponding to the maximum value of the second stress distribution. The monitoring points are the units in the finite element model that are located at the same locations as the vibration sensors at the actual blasting construction site.

[0108] The multiple simulation unit 140 is used to simulate and calculate the finite element model under different charge amounts and different blasting distances to obtain multiple blasting simulation results, which include the maximum tensile stress of the vulnerable point and the maximum vibration velocity of the monitoring point under different charge amounts and different blasting distances;

[0109] The first fitting unit 150 is used to fit the maximum tensile stress of the vulnerable point and the maximum vibration velocity of the monitoring point under different charge amounts and different explosion distances to obtain a first relationship;

[0110] The second fitting unit 160 is used to fit the maximum vibration velocity at the monitoring point and the corresponding charge amount and explosion distance to obtain a second relationship;

[0111] An evaluation unit 170 is configured to obtain a safe allowable vibration velocity at a monitoring point based on the pile foundation structure parameter information and the first relationship, and compare the velocity with the output value of a vibration sensor at an actual blasting construction site to obtain a safety evaluation of the pile foundation structure;

[0112] The calculation unit 180 is used to calculate the safe explosion distance under a certain charge amount or the safe charge amount under a certain explosion distance according to the safe allowable vibration velocity of the monitoring point and the second relationship.

[0113] In some specific embodiments, the modeling unit 110 includes:

[0114] Component modeling unit, used to model concrete and rock soil using Solid164 entity units; and to model steel bars using Beam161 beam units;

[0115] Connection unit, used to set the concrete and steel bars to be connected using the common node method;

[0116] Partitioning unit, used to divide the explosive and air into multi-material ALE grid, divide the rest into Lagrangian grid, and couple the ALE grid and Lagrangian grid through fluid-structure coupling keyword;

[0117] The boundary setting unit is used to set the surrounding areas and bottom of the rock and soil body as non-reflecting boundary conditions; and to set the top of the pile foundation as a fixed constraint.

[0118] In some specific embodiments, the single simulation unit 120 includes:

[0119] Single charge simulation unit, used to simulate a charge that meets actual blasting conditions;

[0120] Single blast distance simulation unit, used to simulate a blast distance that conforms to actual blasting conditions;

[0121] The output unit is used to obtain the results of a single blasting simulation, including the relationship curve between the maximum tensile stress of the pile foundation structure unit and the depth of the unit, and the relationship curve between the maximum tensile stress of the unit on the top cross section of the pile foundation structure and the azimuth angle of the unit.

[0122] In some specific embodiments, the multi-simulation unit 140 includes:

[0123] Multiple charge simulation unit, used to set 200 grams of explosives as a roll and simulate different charge amounts by changing the number of rolls;

[0124] Multiple explosion distance simulation unit, used to obtain different explosion distances by changing the horizontal distance from the center of the explosive to the pile foundation structure;

[0125] The output unit is used to obtain multiple blasting simulation results, including the maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charge amounts and blasting distances.

[0126] Example 3:

[0127] This embodiment provides an application of a method for evaluating the safety of pile foundation structures due to blasting vibration, using the method for evaluating the safety of pile foundation structures due to blasting vibration as described in Example 1, including:

[0128] S210. Before blasting construction, monitoring points can be set up in the occupied space near the pile foundation structure, and vibration sensors are arranged at the monitoring points;

[0129] S220, after blasting construction, obtaining the output value of the vibration sensor;

[0130] S230: Compare the output value of the vibration sensor with the safe allowable vibration velocity of the monitoring point to obtain a safety evaluation of the pile foundation structure.

[0131] This embodiment is easy to implement and is convenient for monitoring the safety of pile foundation structures.

[0132] Example 4:

[0133] This embodiment provides another application of a pile foundation structure blasting vibration safety assessment method, using the pile foundation structure blasting vibration safety assessment method of Example 1, including:

[0134] S310, calculating a safe explosion distance under a certain charge amount or a safe charge amount under a certain explosion distance using the safe allowable vibration velocity at the monitoring point and the second relationship as a safety parameter group;

[0135] S320. Set the charge amount and blasting distance during blasting construction within the range of the safety parameter group.

[0136] By setting the charge amount and blasting distance during blasting within the safety parameter set, this embodiment ensures the safety of the pile foundation structure during blasting, reduces safety accidents caused by structural cracking or damage, and improves the safety and reliability of blasting. Furthermore, the appropriate charge amount can be selected for blasting based on the actual blasting distance allowed for the blasting operation, reducing resource waste caused by inappropriate blasting parameters and improving construction efficiency and quality.

Claims

1. A method for evaluating the safety of pile foundation structure blasting vibration, characterized by: The pile foundation structure blasting vibration safety assessment method comprises the following steps: 1) Obtaining pile foundation structure parameter information; 2) Constructing a finite element model based on the pile foundation structure parameter information obtained in step 1); 3) setting a single blasting condition, and calculating the finite element model constructed in step 2) based on the single blasting condition to obtain a single blasting simulation result; the single blasting condition is a charge amount and a blasting distance that simulates actual blasting conditions; the single blasting simulation result includes a first stress distribution and a second stress distribution; the first stress distribution is a curve showing the relationship between the maximum tensile stress of a pile foundation structure unit and the depth of the pile foundation structure unit; the pile foundation structure unit is a unit grid obtained by dividing the finite element model; the second stress distribution is a curve showing the relationship between the maximum tensile stress of a unit on a cross section at the top of the pile foundation structure and the azimuth angle at which the top of the pile foundation structure is located; 4) Based on the single blasting simulation results obtained in step 3), determine the vulnerable points and monitoring points of the pile foundation structure due to blasting vibration; the vulnerable points are located at the depth corresponding to the maximum value of the first stress distribution and the azimuth corresponding to the maximum value of the second stress distribution; and the monitoring points are the same units in the finite element model as the vibration sensor points at the actual blasting construction site; 5) setting multiple blasting conditions and calculating the finite element model constructed in step 2) based on the multiple blasting conditions to obtain multiple blasting simulation results; the multiple blasting simulation results include the maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charge amounts and different blasting distances; 6) performing fitting based on the multiple blasting simulation results obtained in step 5) to obtain fitting results; 7) Evaluate the blasting vibration safety of the pile foundation structure based on the pile foundation structure parameter information obtained in step 1) and the fitting result obtained in step 6).

2. The pile foundation structure blasting vibration safety assessment method according to claim 1, characterized in that: The pile foundation structural parameter information in step 1) includes pile foundation material parameters, rock and soil material parameters, and pile foundation geometry information; the pile foundation material parameters include density, elastic modulus, Poisson's ratio, and tensile strength of concrete.

3. The pile foundation structure blasting vibration safety assessment method according to claim 2, characterized in that: The specific implementation of step 2) is: 2.1) The concrete and rock-soil mass were modeled using Solid164 solid elements to obtain the concrete rock-soil mass model; 2.2) Model the steel bar using Beam161 beam elements to obtain the steel bar model; 2.3) Connecting the concrete rock-soil model obtained in step 2.1) and the steel bar model obtained in step 2.2) using a common node method; 2.4) Divide the explosives and air into a multi-material ALE grid, and divide the rest into a Lagrangian grid. Then couple the ALE grid and the Lagrangian grid using the fluid-structure coupling keyword. 2.5) Set the surrounding and bottom of the rock mass as non-reflecting boundary conditions; 2.6) Set the top of the pile foundation as a fixed constraint to obtain the finite element model.

4. The pile foundation structure blasting vibration safety assessment method according to claim 3, characterized in that: The multiple blasting conditions in step 5) are to simulate different charge amounts and different blasting distances that are consistent with actual blasting conditions.

5. The method for evaluating the safety of pile foundation structure blasting vibration according to claim 4, characterized in that: The specific implementation of step 6) is: 6.1) Using the least squares method, perform a linear fit between the maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charge loads and different explosion distances to obtain a first relationship, which is expressed as v = a × σ + b; Where: v is the maximum vibration velocity at the monitoring point, σ is the maximum tensile stress at the vulnerable point, and a and b are both unknown coefficients; 6.2) The least squares method is used to perform multivariate nonlinear fitting on the maximum vibration velocity at the monitoring point under different charge amounts and different explosion distances and the corresponding charge amounts and explosion distances, and the second relationship is obtained. The expression of the second relationship is v = c × Q A R B ; Among them, v is the maximum vibration velocity at the monitoring point, Q is the charge amount, R is the explosion distance, and c, A, and B are all unknown coefficients.

6. The method for evaluating the safety of pile foundation structure blasting vibration according to claim 5, characterized in that: The specific implementation of step 7) is: 7.1) Substitute the tensile strength of the pile foundation material parameters as the maximum tensile stress into the first equation to calculate the safe allowable vibration velocity at the monitoring point. Compare this safe allowable vibration velocity at the monitoring point with the output value of the vibration sensor at the actual blasting construction site. If the output value of the vibration sensor is greater than the safe allowable vibration velocity at the monitoring point, the pile foundation structure is considered to be in an unsafe state; otherwise, the pile foundation structure is considered to be in a safe state. 7.2) Substitute the safe allowable vibration velocity at the monitoring point as the maximum vibration velocity at the monitoring point into the second equation to calculate the basis for evaluating the safety of blasting vibrations in pile foundation structures. The basis for evaluating the safety of blasting vibrations in pile foundation structures is the safe blasting distance for a certain charge amount or the safe charge amount for a certain blasting distance.

7. A pile foundation structure blasting vibration safety assessment system for implementing the pile foundation structure blasting vibration safety assessment method according to any one of claims 1 to 6, characterized in that: The pile foundation structure blasting vibration safety assessment system includes: A modeling unit for obtaining pile foundation structure parameter information and constructing a finite element model based on the pile foundation structure parameter information; A simulation unit for performing a single simulation blast or multiple blasts on a finite element model; Fixed-point unit used to identify vulnerable points and monitoring points of pile foundation structures caused by blasting vibration; A fitting unit for fitting multiple blasting simulation results; An evaluation unit for evaluating the blasting vibration safety of the pile foundation structure based on the fitting results and pile foundation structure parameter information; A calculation unit for calculating a finite element model and for calculating a safe explosion distance under a certain charge or a safe charge under a certain explosion distance.

8. The pile foundation structure blasting vibration safety assessment system according to claim 7, characterized in that: The modeling unit includes: A component modeling unit, wherein the component modeling unit is used to model the concrete and rock soil using Solid164 entity elements and to model the steel bars using Beam161 beam elements; A connection unit, wherein the connection unit is used to connect concrete and steel bars using a common node method; A partitioning unit, wherein the partitioning unit is used to partition the explosive and air into a multi-material ALE grid, and to partition the remaining part into a Lagrangian grid, and to couple the ALE grid and the Lagrangian grid through a fluid-structure coupling keyword; A boundary setting unit, wherein the boundary setting unit is used to set the periphery and bottom of the rock and soil body as non-reflecting boundary conditions; and set the top of the pile foundation as a fixed constraint; The simulation unit includes a single simulation unit and a multiple simulation unit; The single simulation unit includes: A single charge simulation unit for simulating a charge that meets actual blasting conditions; A single blast distance simulation unit for simulating a blast distance that conforms to actual blasting conditions; A first output unit for obtaining a single blasting simulation result; The multiple simulation unit includes: A multiple charge simulation unit for simulating different charge amounts by changing the number of rolls; A multiple explosion distance simulation unit for obtaining different explosion distances by changing the horizontal distance from the center of the explosive to the pile foundation structure; A second result output unit for obtaining multiple blasting simulation results.

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