System and method for predicting volume and position of collapse induced by pipeline leakage

Abstract

The invention relates to the technical field of collapse volume and position prediction, in particular to a pipeline leakage induced collapse volume and position prediction system and method, and the system comprises an information collection module, a calculation module, a parameter generation module, a numerical simulation module, an optimization module and a prediction module. By applying the method, necessary preconditions can be provided for accurately preventing and controlling collapse caused by corrosion leakage of the pipeline actively.

Description

Technical Field

[0001] The invention relates to the technical field of collapse volume and position prediction, and in particular to a system and method for predicting collapse volume and position induced by pipeline leakage. Background Art

[0002] With the rapid development of cities in my country, the proportion of various public building pipelines, including hydraulic pipelines, in underground buildings is increasing. Underground hydraulic pipelines are often damaged due to construction or corrosion and aging problems. After leakage occurs, it will further cause soil settlement or even collapse.

[0003] Under the effect of time, the small holes caused by leakage will gradually extend and expand, eventually forming large erosion cavities. The water-saturated soil will increase the weight of the soil in the cavity vault, and the coarse clay particles in the soil will soften after absorbing water, thereby accelerating the deformation of soil particles and eventually forming a large area of ​​soil collapse. Existing scholars have done a lot of research on the monitoring and early warning of collapse caused by leakage, but there are few reports on how to quickly analyze and predict the volume and location of the cavities that may cause collapse. Summary of the invention

[0004] The object of the present invention is to provide a system and method for predicting the collapse volume and position induced by pipeline leakage, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A system for predicting the collapse volume and position caused by pipeline leakage, comprising an information collection module, a calculation module, a parameter generation module, a numerical simulation module, an optimization module, and a prediction module;

[0007] The information collection module is configured to: collect statistics on the on-site soil information of the collapse site and the historical information on hydraulic pipeline damage based on the historical collapse cases induced by existing pipeline leakage;

[0008] The calculation module is configured as follows: according to the collected historical relevant information, the Chinese point leakage model calculation formula is used to solve and calculate the leakage amount per unit time; then the basic physical parameters of the soil are determined by the geological data of the collapsed area, and the volume of the soil collapse caused by the leakage is calculated by combining the calculated leakage amount per unit time and the derived soil collapse calculation formula.

[0009] The parameter generation module is configured to: convert the basic physical parameters of soil and water flow in actual engineering cases into numerical simulation parameters corresponding to discrete element software;

[0010] The numerical simulation module is configured to: use fluid calculation software to simulate the event of pipeline leakage-induced collapse, input simulation parameter information of soil and water flow in actual cases, and achieve the expected effect through the transmission of water pressure and the movement of particles;

[0011] The optimization module is configured to: continuously adjust the permeability coefficient K in the numerical simulation module so that the collapse volume obtained by numerical simulation is approximately close to the actual collapse volume, thereby determining the empirical K value;

[0012] The prediction module is configured to: input corresponding soil and water flow related parameters and empirical K value for the actual project that needs to be predicted later, and predict the collapse shape and position induced by leakage within a preset time.

[0013] A method for predicting the collapse volume and position induced by pipeline leakage comprises the following steps:

[0014] S1: Collect the collapse site information of the existing collapse accident records;

[0015] S2: Calculate the leakage amount by using the Chinese point leakage model; calculate the collapse volume by using the soil collapse calculation formula;

[0016] S3: Convert the basic physical parameters of soil and water flow in the actual case into numerical simulation parameters corresponding to the discrete element software;

[0017] S4: Using fluid software to simulate the process of pipeline leakage-induced collapse, and obtain the collapse volume;

[0018] S5: Continuously adjust the permeability coefficient K to optimize it so that it is close to the actual collapse volume, thereby determining the empirical K value;

[0019] S6: For subsequent actual projects that need to be predicted, the prediction can be achieved by inputting the corresponding soil and water flow related parameters and the empirical K value.

[0020] As a further solution of the present invention: the calculation of the soil collapse volume in S2 needs to determine the soil type based on the collected basic physical properties of the soil, so as to determine the value of the permeability coefficient, and then combine the soil loss equation and the leakage amount to obtain the volume of collapse caused by leakage within a preset time; the specific steps are as follows:

[0021] S201: Based on the collected basic physical parameters of the soil at the engineering case site, determine whether the soil type is cohesive soil or non-cohesive soil;

[0022] S202: determining the corresponding range of internal friction angle values ​​and the increase in soil density after saturation, and obtaining the value of the permeability coefficient in the collapse calculation formula. The permeability coefficient value in the collapse calculation formula is obtained by the shear strength calculation formula corresponding to different types of soil, wherein the shear strength involves the internal friction angle and the increase in soil density after saturation;

[0023] S203: Calculate the actual volume of collapse using the collapse calculation formula corresponding to different soil types; combine the soil loss equation and the leakage amount to derive the collapse calculation formula for different soils; the derived non-cohesive soil collapse calculation formula is:

[0024] C=ln(2.1+0.52ρ 土 QK 1 TCOSθ)

[0025] The derived calculation formula for clay soil collapse is:

[0026] C=0.52ρ 土 QK 1 TCOSθ

[0027] In the above two formulas: Q represents the seepage rate, the unit is m3 / s, K 1 represents the soil permeability coefficient, T represents the seepage time, θ represents the angle between the pipe damage port and the horizontal plane, ρ 土 Represents the density of soil particles.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: by collecting relevant information of existing collapse accident records to calculate the leakage amount, and combining the collapse amount formula of different soil bodies to calculate the volume of the collapse. By using fluid calculation software for simulation, by continuously adjusting the permeability coefficient K value, an approximate value of the actual collapse volume is obtained, and the optimization of the K value is realized. After obtaining the empirical K value, for the actual project that needs to be predicted later, the relevant simulation parameters after the soil body and water flow conversion corresponding to the local project are input, and then the empirical K value is input to realize the prediction of the volume and location of the possible collapse.

[0029] The system for predicting the volume and position of collapse induced by pipeline leakage provided by the present invention can accurately locate the volume and position of the possible collapse, and can provide the necessary prerequisite for actively realizing accurate prevention and control of collapse caused by pipeline leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0031] Figure 2 This is a schematic diagram of the calculation process of soil collapse induced by leakage;

[0032] Figure 3 Schematic diagram of the model of soil grid, boundary and node. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0034] See also Figure 1-3 , the present invention provides a system for predicting the collapse volume and position induced by pipeline leakage, the structure of which includes an information collection module, a calculation module, a parameter generation module, a numerical simulation module, an optimization module, and a prediction module;

[0035] The information collection module is configured to: based on historical collapse cases caused by existing pipeline leakage, collect statistics on on-site soil information of the collapse site and historical information on hydraulic pipeline damage; specific information includes soil density, soil plasticity index, shape and size of the leakage port, water pressure at the damaged port of the hydraulic pipeline, water flow velocity, etc.

[0036] The calculation module is configured to: calculate the leakage amount per unit time by solving the Chinese point leakage model calculation formula according to the collected historical relevant information; the Chinese point leakage model calculation formula is:

[0037]

[0038] Where: Q 漏 is the water leakage, in m 3 / s, A is the damaged area, unit is m 2 , p is the pressure on the damaged section, in m;

[0039] Then, the basic physical parameters of the soil are determined from the geological data of the collapsed area. The volume of the soil collapse caused by the leakage is calculated by combining the calculated leakage loss per unit time with the derived equation for the soil collapse volume.

[0040] The parameter generation module is configured to: convert the basic physical parameters of soil and water flow in actual engineering cases into numerical simulation parameters corresponding to discrete element software;

[0041] The numerical simulation module is configured to: use fluid calculation software to simulate the event of pipeline leakage-induced collapse, input simulation parameter information of soil and water flow in actual cases, and achieve the expected effect through the transmission of water pressure and the movement of particles;

[0042] The optimization module is configured to: continuously adjust the permeability coefficient K in the numerical simulation module so that the collapse volume obtained by numerical simulation is approximately close to the actual collapse volume, thereby determining the empirical K value;

[0043] The prediction module is configured to input the corresponding soil and water flow related parameters and the empirical K value for the actual project that needs to be predicted later, and predict the collapse shape and position induced by leakage within a preset time. The collapse contour obtained by numerical simulation and its position from the pipeline leakage can be used as the basis for the diffusion trend of the leakage water flow to the surrounding areas and the prediction of the collapse volume and position.

[0044] The present invention provides a method for predicting the collapse volume and position induced by pipeline leakage, comprising the following steps:

[0045] S1: Collect the collapse site information of the existing collapse accident records;

[0046] S2: Calculate the leakage amount by using the Chinese point leakage model; calculate the collapse volume by using the soil collapse calculation formula;

[0047] S3: Convert the basic physical parameters of soil and water flow in the actual case into numerical simulation parameters corresponding to the discrete element software;

[0048] S4: Using fluid calculation software to simulate the process of pipeline leakage-induced collapse, and obtain the collapse volume;

[0049] A fluid grid is established in the fluid calculation software and the corresponding node information is stored in the grid. After defining the impermeable boundary, different water pressures are applied to the upper and lower boundaries to achieve the desired effect through the transfer of water pressure and the movement of particles.

[0050] Specifically, based on the collapse size, a cube with a boundary larger than the collapse size is established using fluid calculation software as a soil model. Particles are spheres of different sizes, which are randomly distributed, and the particles are connected using linear contact.

[0051] Specifically, the input parameters in the model are calibrated to convert the soil parameters in the actual project into parameters suitable for numerical simulation. Through Brazilian splitting test, biaxial test, seepage test, by comparing the Poisson's ratio, internal friction angle, cohesion, elastic modulus, permeability coefficient and other parameters in the soil geotechnical test and numerical model, the tangential stiffness, normal stiffness, friction coefficient, normal bond strength and tangential bond strength are calibrated.

[0052] Take a kind of clay as an example: the soil parameters in the actual project and the parameters in the simulation are shown in Table 1, and the calibration values ​​are shown in Table 2.

[0053] Table 1

[0054]

[0055] Table 2

[0056]

[0057] Specifically, the information of the grid nodes is stored when the model is initially established and the model is divided into grids. Figure 3 The discrete reference steady flow equation of the fluid between nodes in the grid is shown as follows: Where u represents the water head.

[0058] Fipy, a fluid computing software, is mainly used to solve partial differential equations. Its seamless integration with other Python libraries gives it a unique advantage in fluid computing, and its powerful numerical solution capabilities enable it to support a variety of complex physical models.

[0059] For actual projects that need to be predicted later, input the relevant simulation parameters after the soil and water flow conversion corresponding to the local project, and then input the empirical K value to achieve accurate prediction of the volume and location of possible collapse.

[0060] S5: Continuously adjust the permeability coefficient K to optimize it so that it is close to the actual collapse volume, thereby determining the empirical K value;

[0061] S6: For subsequent actual projects that need to be predicted, the prediction can be achieved by inputting the corresponding soil and water flow related parameters and the empirical K value.

[0062] The calculation of the soil collapse volume in S2 requires judging the soil type based on the collected basic physical properties of the soil, thereby determining the value of the permeability coefficient, and then combining the soil loss equation with the leakage amount to obtain the volume of collapse caused by leakage within a preset time; the specific steps are as follows:

[0063] S201: Based on the collected basic physical parameters of the soil at the engineering case site, determine whether the soil type is cohesive soil or non-cohesive soil;

[0064] S202: determining the corresponding range of internal friction angle values ​​and the increase in soil density after saturation, and obtaining the value of the permeability coefficient in the collapse calculation formula. The permeability coefficient value in the collapse calculation formula is obtained by the shear strength calculation formula corresponding to different types of soil, wherein the shear strength involves the internal friction angle and the increase in soil density after saturation;

[0065] S203: Calculate the actual volume of collapse using the collapse calculation formula corresponding to different soil types; combine the soil loss equation and the leakage amount to derive the collapse calculation formula for different soils; the derived non-cohesive soil collapse calculation formula is:

[0066] C=ln(2.1+0.52ρ ± QK 1 TCOSθ)

[0067] The derived calculation formula for clay soil collapse is:

[0068] C=0.52ρ ± QK 1 TCOSθ

[0069] In the above two formulas: Q represents the seepage rate, the unit is m3 / s, K 1 represents the soil permeability coefficient, T represents the seepage time, θ represents the angle between the pipe damage port and the horizontal plane, ρ 土 Represents the density of soil particles.

[0070] It should be noted that after the soil is saturated, the weight of the soil increases, resulting in an increase in the self-weight of the soil in the cavity vault, and eventually a large collapse. Fine-grained soil is lost in large quantities during the infiltration of water to form small cavities. After the cavities are generated, the permeability coefficient will increase, thereby increasing the dynamic water pressure of the soil, thereby accelerating the collapse. Therefore, the permeability coefficient of the soil and the increase in the weight of the soil after saturation are important factors affecting the final collapse volume.

[0071] like Figure 2 As shown in the figure, the permeability coefficient of the soil is related to the tangent value of the effective internal friction angle of the soil, and the effective internal friction angle of the soil and the increase in the weight after the soil is saturated vary depending on the soil type. The internal friction angle of cohesive soil is 18-22°, the tangent value is about 0.32-0.46, and the internal friction angle of cohesive soil is 26-48°, and the tangent value is about 0.49-1.11.

[0072] According to the increase in the weight of the soil after saturation, for clay soil, the weight of the soil after saturation can increase by 1 / 7-2 / 7, and for non-cohesive soil, the weight of the soil after saturation can increase by 5%-6%.

[0073] From a safety perspective, the range of internal friction angles for different soils and the increase in soil density after saturation are considered based on the most unfavorable factors.

[0074] The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A system for predicting the volume and location of collapse caused by pipeline leakage, characterized in that: It includes information collection module, calculation module, parameter generation module, numerical simulation module, optimization module and prediction module; The information collection module is configured to: collect statistics on the on-site soil information of the collapse site and the historical information on hydraulic pipeline damage based on the historical collapse cases induced by existing pipeline leakage; The calculation module is configured to: calculate the leakage amount per unit time by solving the calculation formula of the Chinese point leakage model according to the collected historical relevant information; then determine the basic physical parameters of the soil body according to the geological data of the collapsed area, and calculate the volume of the soil collapse caused by the leakage by combining the calculated leakage amount per unit time and the derived soil collapse calculation formula; The parameter generation module is configured to: convert the basic physical parameters of soil and water flow in actual engineering cases into numerical simulation parameters corresponding to discrete element software; The numerical simulation module is configured to: use fluid calculation software to simulate the event of pipeline leakage-induced collapse, input simulation parameter information of soil and water flow in actual cases, and achieve the expected effect through the transmission of water pressure and the movement of particles; The optimization module is configured to: continuously adjust the permeability coefficient K in the numerical simulation module so that the collapse volume obtained by numerical simulation is approximately close to the actual collapse volume, thereby determining the empirical K value; The prediction module is configured to: input corresponding soil and water flow related parameters and empirical K value for the actual project that needs to be predicted later, and predict the collapse shape and position induced by leakage within a preset time.

2. A method for predicting the volume and location of collapse induced by pipeline leakage, characterized in that: The following steps are involved: S1: Collect the collapse site information of the existing collapse accident records; S2: Calculate the leakage amount by using the Chinese point leakage model; calculate the collapse volume by using the soil collapse calculation formula; S3: Convert the basic physical parameters of soil and water flow in the actual case into numerical simulation parameters corresponding to the discrete element software; S4: Use fluid software to simulate the process of pipeline leakage-induced collapse and obtain the collapse volume; S5: Continuously adjust the permeability coefficient K to optimize it so that it is close to the actual collapse volume, thereby determining the empirical K value; S6: For subsequent actual projects that need to be predicted, the prediction can be achieved by inputting the corresponding soil and water flow related parameters and the empirical K value.

3. The method for predicting the collapse volume and position caused by pipeline leakage according to claim 2, characterized in that: The calculation of the soil collapse volume in S2 requires judging the soil type based on the collected basic physical properties of the soil, thereby determining the value of the permeability coefficient, and then combining the soil loss equation with the leakage amount to obtain the volume of collapse caused by leakage within a preset time; the specific steps are as follows: S201: Based on the collected basic physical parameters of the soil at the engineering case site, determine whether the soil type is cohesive soil or non-cohesive soil; S202: determining the corresponding range of internal friction angle values ​​and the increase in soil density after saturation, and obtaining the value of the permeability coefficient in the collapse calculation formula. The permeability coefficient value in the collapse calculation formula is obtained by the shear strength calculation formula corresponding to different types of soil, wherein the shear strength involves the internal friction angle and the increase in soil density after saturation; S203: Calculate the actual volume of collapse using the collapse calculation formula corresponding to different soil types; combine the soil loss equation and the leakage amount to derive the collapse calculation formula for different soils; the derived non-cohesive soil collapse calculation formula is: c=ln(2.1+0.52ρ 土 QK1TCOSθ) The derived formula for calculating the amount of clay soil collapse is: C=0.52ρ 土 QK1TCOSθ In the above two formulas, Q represents the seepage rate in m3 / s, K1 represents the soil permeability coefficient, T represents the seepage time, θ represents the angle between the damaged pipe and the horizontal plane, and ρ 土 Represents the density of soil particles.

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