Safety evaluation method for blasting vibration of pile foundation structure

Abstract

The invention belongs to the technical field of blasting, and relates to a pile foundation structure blasting vibration safety evaluation method which comprises the following steps: 1) acquiring pile foundation structure parameter information; 2) constructing a finite element model; 3) setting a single blasting condition and calculating the finite element model; 4) confirming blasting vibration vulnerable points and monitoring points of the pile foundation structure; 5) setting multiple blasting conditions and calculating the finite element model; according to the method for evaluating the blasting vibration safety of the pile foundation structure, a scientific basis can be provided for evaluating the blasting vibration safety of the pile foundation structure, a blasting construction scheme can be helped to be determined, and the quality and safety of the blasting construction process can be guaranteed.

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 the development of cities, urban blasting projects have increased, including foundation pit blasting excavation, subway tunnel blasting excavation, building demolition blasting, etc. Assessing the impact of the harmful effects of blasting vibration on adjacent buildings is the key to ensuring the safety of life and property and the timely delivery of engineering projects. At present, the safety evaluation of urban building blasting relies solely on the safe allowable vibration velocity of particles recommended in the "Safety Regulations for Blasting (GB6722-2014)". The reference values ​​proposed in this specification are empirical and general, and cannot provide flexible judgment standards based on the characteristics of the project. In addition, this specification does not clearly stipulate the safe allowable vibration velocity of blasting vibration of pile foundation structures such as viaducts and civil buildings, and lacks a means of evaluating the safe charge and safe blasting distance of blasting construction adjacent to pile foundation structures. Summary of the invention

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

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

[0005] A method for evaluating the safety of pile foundation structure blasting vibration, characterized in that the 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 according to 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 in 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 in the present invention is:

[0015] 2.1) The concrete and rock-soil bodies are modeled using Solid164 entity units to obtain a concrete rock-soil body model;

[0016] 2.2) The steel bar is modeled 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 explosive and air into multi-material ALE grids, divide the rest into Lagrangian grids, and couple the ALE grid and Lagrangian grid through the fluid-structure coupling keyword;

[0019] 2.5) Set the surrounding and bottom of the rock and soil body 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 that simulates actual blasting conditions 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 relationship curve 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 relationship curve between the maximum tensile stress of the unit on the cross section at the top of the pile foundation structure and the azimuth angle at the top of the pile foundation structure.

[0022] Preferably, the vulnerable point in step 4) adopted in the present invention is located at a depth corresponding to the maximum value of the first stress distribution and an 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 that conform to actual blasting conditions and to simulate 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) The maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charges and different explosion distances are linearly fitted by the least square method to obtain a first relationship, the expression of which is v=a×σ+b; wherein: 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;

[0026] 6.2) The least square method is used to perform multivariate nonlinear fitting on the maximum vibration velocity of the monitoring point under different charges and different explosion distances and the corresponding charges and explosion distances to obtain the second relationship, which is expressed as 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 in the pile foundation material parameters as the maximum tensile stress into the first relational equation, calculate the safe allowable vibration velocity at the monitoring point, and 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 of the monitoring point as the maximum vibration velocity of the monitoring point into the second relational equation, the safety evaluation basis of the blasting vibration of the pile foundation structure is calculated, and the safety evaluation basis of the 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, characterized in that: the pile foundation structure blasting vibration safety evaluation system comprises:

[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 burst or multiple bursts of a finite element model;

[0033] Fixed-point unit used to confirm the vulnerable points and monitoring points of the pile foundation structure due to 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 the 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 units and to model the steel bars using Beam161 beam units;

[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 the air into a multi-material ALE grid, and the rest into a Lagrangian grid, and couple the ALE grid and the Lagrangian grid through a fluid-solid coupling keyword;

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

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

[0043] The single simulation unit comprises:

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

[0045] A single blast distance simulation unit used to simulate 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 comprises:

[0048] A multiple charge simulation unit for simulating different charge amounts by changing the number of medicine 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 invention provides a method for evaluating the safety of blasting vibration 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 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; 6) fitting is performed according to the multiple blasting simulation results obtained in step 5) to obtain a fitting result; 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 result obtained in step 6). The present invention obtains the vulnerable points of the pile foundation structure after blasting construction, the relationship between the maximum tensile stress of the vulnerable points and the maximum vibration velocity of the monitoring points, the relationship between the maximum vibration velocity of the monitoring points and the charge amount and the blasting distance through simulation, analysis and calculation. Combined with the pile foundation structure parameter information and the above relationship, the safe allowable vibration velocity of the monitoring point and the safe charge amount and safe blasting distance of the 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 of the monitoring point to realize the safety evaluation of the pile foundation structure blasting. The present invention can not only provide a scientific basis for the safety evaluation of the blasting vibration of the pile foundation structure, but also help 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 schematic flow chart of the blasting vibration safety evaluation method for pile foundation structure 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 and the depth of the unit;

[0055] Figure 3 It is a curve of the relationship between the maximum tensile stress of the 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 blasting vibration safety evaluation system for pile foundation structure 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 evaluation 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] Embodiment 1:

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

[0064] S1. Obtaining pile foundation structure parameter information, and constructing a finite element model according to 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, concrete and rock and soil are modeled using Solid164 entity units;

[0067] S12, the steel bar is modeled using Beam161 beam element;

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

[0069] S14, divide the explosive and air into multi-material ALE grids, divide the rest into Lagrangian grids, and couple the ALE grid and Lagrangian grid through the fluid-solid coupling keyword;

[0070] S15. Set the surrounding 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 are simulated using the MAT-HIGH-EXPLOSIVE-BURN material model, and the EOS_JWL state equation is 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 state equation 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 of the high-pressure gas generated by the explosion on the cladding and the surrounding medium, thereby providing more accurate simulation results.

[0074] The air is simulated using the MAT-NULL material model, and the linear polynomial state equation EOS-LINEAR-POLYNOMIAL state equation is used to calculate the pressure during the blasting simulation; the linear polynomial state equation can simulate the ideal gas state equation 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 ​​​​the explosion pressure, while also ensuring good consistency with the experimental data, and improving the predictive ability and reliability of the model.

[0075] The steel bars are 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 loading.

[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 changing laws of the initial yield strength, failure strength and residual strength of concrete.

[0077] S2, simulate and calculate the finite element model under a charge amount and a 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 of the relationship between the maximum tensile stress of the pile foundation structure unit and the depth of the unit, and the second stress distribution is a curve of 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. In some specific embodiments, step S2 specifically includes:

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

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

[0080] S23 obtains the single blasting simulation results, 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.

[0081] In this embodiment, a charge of 4 kg and a blasting distance of 40 m are preset. The relationship curve between the maximum tensile stress of the unit on one side of the pile foundation structure and the depth of the pile foundation obtained by simulation 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. According to the relationship curve between the maximum tensile stress of the unit and the depth of the pile foundation and the relationship curve between the maximum tensile stress of the unit and the azimuth angle of the unit, it can be obtained that the vulnerable point of the pile foundation blasting vibration is located on the back blasting side of the top of the pile foundation. In this embodiment, the preset on-site blasting monitoring point is located 50 cm away from the back blasting side of the top of the pile foundation, and a vibration sensor is arranged at the monitoring point.

[0083] S4. Simulate and calculate the finite element model under different charges 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 charges and different blasting distances.

[0084] In this embodiment, different charge weights are preset to be 4kg, 6kg, 8kg, 10kg, and 12kg, and different blasting distances between the explosive and the pile foundation are 20m, 30m, 40m, 50m, and 60m, respectively. The monitoring point is located 50cm from the back blasting 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 of the vulnerable point and the maximum vibration velocity of the monitoring point under different charges and different explosion distances to obtain the first relationship.

[0089] The maximum tensile stress at the vulnerable point and the maximum vibration velocity at 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 output value of the vibration sensor at the actual blasting construction site is compared to obtain the pile foundation structure safety evaluation.

[0095] In this embodiment, the pile foundation structure concrete adopts C30 concrete, and the tensile strength design value is 1.43MPa. Substituting this value into the first relational equation, the safe allowable vibration velocity of the monitoring point is 1.3cm / 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 <1.3cm / s, the pile foundation structure is safe;

[0097] When the output value of the vibration sensor is >1.3cm / 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 according to the safe allowable vibration velocity of the monitoring point and the second relationship.

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

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

[0101] Or R = 14.4 × Q 0.42 , substituting the actual charge at the blasting construction site into the formula, the corresponding safe explosion distance can be obtained. For charges of 4kg, 6kg, 8kg, 10kg, and 12kg, the calculated safe explosion 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 the relationship between the charge, blasting distance, maximum tensile stress at the vulnerable point and the 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 blasting vibration of pile foundation structures, but also can provide a reference for similar projects in the future, especially in preventing and dealing with the safety of pile foundation structures caused by blasting. The data and experience accumulated through this method can provide a scientific basis for the safe construction of pile foundation structures near blasting.

[0103] Embodiment 2:

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

[0105] A 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, 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 the 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 the unit on the top cross section of the pile foundation structure and the azimuth of the unit.

[0107] Fixed point unit 130, used to confirm 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 units in the finite element model that are the same as the vibration sensor points at the actual blasting construction site;

[0108] The multiple simulation unit 140 is used to simulate and calculate the finite element model under different charges and different blasting distances to obtain multiple blasting simulation results, wherein 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 charges 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 of the monitoring point and the corresponding charge amount and explosion distance to obtain a second relationship;

[0111] An evaluation unit 170 is used to obtain the safe allowable vibration velocity of the monitoring point according to the pile foundation structure parameter information and the first relationship, and compare it with the output value of the vibration sensor at the 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 and soil using Solid164 entity unit; and to model steel bars using Beam161 beam unit;

[0115] Connection unit, used to set the concrete and steel bars to be connected by 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 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.

[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 meets 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 of the unit.

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

[0123] Multiple charge simulation unit, used to set 200 grams of explosive 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 of the vulnerable point and the maximum vibration velocity of the monitoring point under different charges and different blasting distances.

[0126] Embodiment 3:

[0127] This embodiment provides an application of a method for evaluating the safety of pile foundation structure blasting vibration, using the method for evaluating the safety of pile foundation structure blasting vibration as in Embodiment 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 can be arranged at the monitoring points;

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

[0130] S230, comparing 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 the pile foundation structure.

[0132] Embodiment 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 embodiment 1, including:

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

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

[0136] This embodiment can ensure the safety of the pile foundation structure during the blasting construction process by setting the charge amount and blasting distance during the blasting construction within the range of the safety parameter group, reduce safety accidents caused by structural cracking or damage, and improve the safety and reliability of the blasting construction. It can also select a suitable charge amount for the blasting construction according to the blasting distance allowed by the actual blasting construction, reduce the waste of resources caused by inappropriate blasting parameters, and improve construction efficiency and quality.

Claims

1. A method for evaluating the safety of pile foundation structure blasting vibration, characterized in that: The blasting vibration safety assessment method for pile foundation structure 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; 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); 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; 6) performing fitting according to 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 method for evaluating the safety of pile foundation structure blasting vibration 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 method for evaluating the safety of pile foundation structure blasting vibration according to claim 2, characterized in that: The specific implementation method of step 2) is: 2.1) The concrete and rock-soil bodies are modeled using Solid164 entity units to obtain a concrete rock-soil body model; 2.2) The steel bar is modeled using Beam161 beam elements to obtain a steel bar model; 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; 2.4) Divide the explosive and air into multi-material ALE grids, divide the rest into Lagrangian grids, and couple the ALE grid and Lagrangian grid through the fluid-structure coupling keyword; 2.5) Set the surrounding and bottom of the rock and soil body as non-reflecting boundary conditions; 2.6) Set the top of the pile foundation as a fixed constraint and obtain the finite element model.

4. The method for evaluating the safety of pile foundation structure blasting vibration according to claim 3, characterized in that: The single blasting condition in the step 3) 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 at the top of the pile foundation structure and the azimuth angle at the top of the pile foundation structure.

5. The method for evaluating the safety of pile foundation structure blasting vibration according to claim 4, characterized in that: In the step 4), the vulnerable point is located at a depth corresponding to the maximum value of the first stress distribution and an azimuth corresponding to the maximum value of the second stress distribution; the monitoring point is a unit in the finite element model that is identical to the position of the vibration sensor at the actual blasting construction site.

6. The method for safety assessment of pile foundation structure blasting vibration according to claim 5, characterized in that: The multiple blasting conditions in step 5) are to simulate different charge amounts that conform to actual blasting conditions and to simulate different blasting distances that conform to actual blasting conditions.

7. The method for evaluating the safety of pile foundation structure blasting vibration according to claim 6, characterized in that: The specific implementation method of step 6) is: 6.1) The maximum tensile stress at the vulnerable point and the maximum vibration velocity at the monitoring point under different charges and different explosion distances are linearly fitted by the least square method to obtain a first relationship, wherein 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 unknown coefficients; 6.2) The least square method is used to perform multivariate nonlinear fitting on the maximum vibration velocity of the monitoring point under different charges and different explosion distances and the corresponding charges and explosion distances to obtain the second relationship, which is expressed as 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.

8. The method for evaluating the safety of pile foundation structure blasting vibration according to claim 7, characterized in that: The specific implementation of step 7) is: 7.1) Substitute the tensile strength in the pile foundation material parameters as the maximum tensile stress into the first relational equation, calculate the safe allowable vibration velocity at the monitoring point, and 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; 7.2) Substituting the safe allowable vibration velocity of the monitoring point as the maximum vibration velocity of the monitoring point into the second relational equation, the safety evaluation basis of the blasting vibration of the pile foundation structure is calculated, and the safety evaluation basis of the 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.

9. 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 8, characterized in that: The pile foundation structure blasting vibration safety assessment system comprises: 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 burst or multiple bursts of a finite element model; Fixed-point unit used to confirm the vulnerable points and monitoring points of the pile foundation structure due to 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 the 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.

10. The blasting vibration safety assessment system for pile foundation structure according to claim 9, characterized in that: The modeling unit comprises: A component modeling unit, wherein the component modeling unit is used to model the concrete and rock soil using Solid164 entity units and to model the steel bars using Beam161 beam units; 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 the air into a multi-material ALE grid, and the rest into a Lagrangian grid, and couple the ALE grid and the Lagrangian grid through a fluid-solid coupling keyword; A boundary setting unit, wherein the boundary setting unit is used to set the surroundings and bottom of the rock and soil body to non-reflection boundary conditions; and set the top of the pile foundation to a fixed constraint; Preferably, the simulation unit includes a single simulation unit and a multiple simulation unit; The single simulation unit comprises: A single charge simulation unit for simulating a charge that meets actual blasting conditions; A single blast distance simulation unit used to simulate a blast distance that conforms to actual blasting conditions; A first output unit for obtaining a single blasting simulation result; The multiple simulation unit comprises: A multiple charge simulation unit for simulating different charge amounts by changing the number of medicine 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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