Safety evaluation method for polyethylene gas pipeline under ground contact impact of blasting demolition collapse body

A technology for gas pipeline and safety evaluation, applied in impact testing, testing of machine/structural components, complex mathematical operations, etc., can solve problems such as the difficulty of effective evaluation of hazards, reduce engineering difficulty, strengthen engineering significance, and ensure engineering safety. Effect

Active Publication Date: 2021-10-15
SOUTHWEST PETROLEUM UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention provides a safety evaluation method for polyethylene gas pipelines under the ground impact of blasting and demolition collapsed bodies to solve the problem in the prior art that it is difficult to carry out damages to urban buried polyethylene gas pipelines caused by ground impact of collapsed bodies during blasting and demolition of buildings. The problem of effective evaluation, to achieve the purpose of providing effective reference for blasting engineering construction, and providing scientific and reasonable judgment basis for the protection of buried polyethylene gas pipelines during blasting construction

Method used

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  • Safety evaluation method for polyethylene gas pipeline under ground contact impact of blasting demolition collapse body
  • Safety evaluation method for polyethylene gas pipeline under ground contact impact of blasting demolition collapse body
  • Safety evaluation method for polyethylene gas pipeline under ground contact impact of blasting demolition collapse body

Examples

Experimental program
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Effect test

Embodiment 1

[0093] Such as figure 1 The safety evaluation method for polyethylene gas pipelines under the impact of blasting and demolition collapsed bodies is shown. The PE100 grade HDPE (high density polyethylene) SDR17 (outer diameter / wall thickness = 17) pipeline is used as the research object. The specific evaluation steps include: :

[0094] Step S1: Carry out stress analysis on the buried polyethylene gas pipeline, and calculate the load on the buried polyethylene gas pipeline due to ground impact P P ,Calculated as follows:

[0095]

[0096] In the formula, P max is the maximum impact load on the ground surface; H is the thickness of the covering soil layer above the buried polyethylene gas pipeline; L is the horizontal distance between the ground contact impact load point and the buried polyethylene gas pipeline; where P max The calculation formula is as follows:

[0097]

[0098] In the formula, n is the impact coefficient, V is the velocity of the collapsed bo...

Embodiment 2

[0104] The method for evaluating the safety of polyethylene gas pipelines under the impact of blasting and demolishing collapsed objects on the ground, on the basis of Example 1, the specific implementation process of steps S2-S3 is as follows:

[0105] According to the tensile test results of PE100 grade high-density polyethylene pipes in this embodiment, the engineering stress-strain curve is obtained, and the calculation formula of the yield strength of PE100 under different rates is obtained by fitting:

[0106]

[0107] is the yield stress at the corresponding tensile rate, MPa; v is the uniaxial tensile rate of the pipe, mm / min.

[0108] Substituting different PE100 pipe tensile rates according to this formula can predict the corresponding engineering stress when the pipe yields .

[0109] The real stress at yield can be obtained by substituting the predicted engineering stress into the following formula:

[0110]

[0111] is the engineering stress; is th...

Embodiment 3

[0127] On the basis of any of the above embodiments, this embodiment refines step S4:

[0128] For the establishment of the pipe-soil finite element model of the pipeline without defects: the Drucker-Prager model is selected, which can well simulate the elastic-plastic state of the material under load impact, and there will be no instability in the calculation of large deformation; The grade selects PE100 gas transmission pipeline, and its density is 951kg / m 3 , the tensile rate of the HDPE pipe under the impact load is about 300mm / min; according to the method described in the above examples, the yield strength of the pipe is 27.4MPa and the modulus of elasticity is 1115MPa. The collapsing body adopts the plane touch-to-ground contact method, and the collapsing body is set as a low-height cuboid, 2m long, 0.5m high, and 1m wide. The pipe diameter is preset to 110mm, the wall thickness is 6.5mm, and the covering soil thickness is 0.8m.

[0129] Fully consolidated constraints a...

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Abstract

The invention discloses a safety evaluation method for a polyethylene gas pipeline under blasting demolition collapse body grounding impact. The method comprises the following steps of calculating a load acting on a buried polyethylene pipeline by the grounding impact; performing a tensile test to obtain real stress and real strain; substituting the real stress and the real strain into the hyperbolic constitutive model of the buried polyethylene pipeline to obtain the elastic modulus of the buried polyethylene pipeline; establishing a pipe-soil finite element model, substituting the elastic modulus into the pipe-soil finite element model, and performing dynamic response simulation to obtain stress distribution; and finally, evaluating safety of the buried polyethylene pipeline under the ground contact impact of the blasting demolition collapse body. The method is used for solving a problem that in the prior art, damage to the urban buried polyethylene gas pipeline caused by the ground contact impact of a collapse body during blasting demolition of a building is difficult to effectively assess; effective reference is provided for blasting engineering construction, and scientific and reasonable judgment basis is provided for protection of the buried polyethylene gas pipeline during blasting construction.

Description

technical field [0001] The invention relates to the fields of gas pipelines and blasting demolition, in particular to a safety evaluation method for polyethylene gas pipelines under the impact of a collapsed body in blasting demolition. Background technique [0002] Traditional buried steel gas pipelines are prone to leakage due to corrosion, causing major safety accidents. Compared with steel gas pipelines, buried polyethylene pipes (PE pipes) have many advantages, such as excellent toughness, light weight, corrosion resistance, low temperature resistance, earthquake resistance, and strong economic advantages. Internationally, PE pipe materials are divided into five grades: PE32, PE40, PE63, PE80 and PE100. The material achieves a breakthrough in long-term hydrostatic strength, while also improving resistance to slow crack growth and fast crack growth. In the past ten years, PE pipes have accounted for more than 70% of domestic urban gas pipeline network construction, and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01M7/08G06F30/20G06F17/10
CPCG01M7/08G06F30/20G06F17/10
Inventor 安兆暾黄云飞刘思铭李虎胡刚王璟
Owner SOUTHWEST PETROLEUM UNIV
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