A Calculation Method for Debris Flow Scouring Bridge Piers

A calculation method, technology of debris flow, applied in the field of calculation, can solve problems such as not considering debris flow, large difference, etc.

Active Publication Date: 2021-02-02
CHINA RAILWAY ERYUAN ENG GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this formula does not take into account the characteristics of the debris flow itself, such as the fraction of debris flow, solid-liquid fraction, particle composition ratio, particle size, etc. directly applicable to the calculation of debris flow scoured bridge piers

Method used

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  • A Calculation Method for Debris Flow Scouring Bridge Piers
  • A Calculation Method for Debris Flow Scouring Bridge Piers
  • A Calculation Method for Debris Flow Scouring Bridge Piers

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0135] A calculation method for stone flow scouring bridge piers, comprising the following steps:

[0136] Step 1: Establish erosion rate formula for bridges scoured by debris flow

[0137] Assuming that the debris flow is a homogeneous mixture and is in an incompressible state during the movement, the two-dimensional shallow water wave erosion numerical model can be expressed as:

[0138]

[0139] In the formula: h—debris flow thickness, t—time, u, v—debris flow downstream and lateral velocity along the surface, e b - erosion rate;

[0140] Integrating the above formula along the depth direction, we can get:

[0141]

[0142]

[0143] In the formula:

[0144] u bot , v bot ——Boundary velocity of debris flow base;

[0145] ρ——volume fraction of debris flow and solid phase α s The relevant debris flow density, where ρ=(1-α s )ρ f +α s ρ s , ρ s and ρ f represent the densities of the solid and liquid phases of the debris flow, respectively;

[0146] τ bx ...

Embodiment 2

[0226] The difference between this embodiment and Example 1 is that the calculation method also includes step 4: sensitivity analysis, for different solid phase volume fractions α s Simulate the erosion process of the debris flow below, and compare the calculation results. figure 2 The comparison of the erosion degree of debris flow at the same time under different solid phase volume fractions is shown. When the solid phase volume fractions are 0.35, 0.5, and 0.8, the maximum erosion depths are 0.52m, 1.51m, and 2.52m, respectively. It can be seen that the solid phase The larger the volume fraction, the stronger the scour ability of debris flow, and the greater the harm to bridge piers.

[0227] Also includes step 5, said step 5 is based on the calculation result of said step 4, amending the 65-1 correction formula in the "Code for Hydrological Survey and Design of Highway Engineering" to obtain the formula for the depth of debris flow scoured bridge pier:

[0228] When V≤V ...

Embodiment 3

[0234] The difference between this embodiment and embodiment 1 is that the calculation method also includes step 4: sensitivity analysis, the average particle size of different riverbed sediments Simulate the erosion process of debris flow. like image 3 As shown, taking a simple dam break experiment as an example, the erosion degree of the sediment particle size is 3mm, 8mm, 10mm, 16mm, and 24mm. It can be seen that as the particle size of the base sediment increases, its erosion degree decreases.

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Abstract

The invention discloses a calculation method for debris flow scouring bridge piers, including establishing an erosion rate formula for debris flow scouring bridges: assuming that debris flow is a uniform mixture and in an incompressible state during movement, an empirical parameter ξ is introduced to obtain a revised erosion rate Formula; Numerical calculation is completed according to the physical parameters of the working conditions determined by the debris flow scouring the bridge: the revised erosion rate calculation formula is converted into vector form and discretized in time and space, the physical parameters of the debris flow are determined and assigned, and the finite volume method is used Solve the flux Riemann problem; solve the above discrete equations and calculation formats in the x and y directions, and judge the erosion conditions according to the revised erosion rate formula, thereby completing a calculation cycle; visualize the results to obtain the erosion information : Using computer graphics and image processing technology, the calculation data is converted into graphics or image output, and the conclusion of debris flow scouring bridge piers is obtained.

Description

technical field [0001] The invention relates to a calculation method, in particular to a calculation method for debris flow scoured bridge piers. Background technique [0002] Debris flow is widely distributed in the mountainous areas of our country, and it is one of the most destructive mountain disasters, which poses a great threat to the economic development of mountainous areas and the safety of people's lives and properties. When a debris flow breaks out, the huge scouring effect may lead to the instability of the bridge pier; the deposition of the debris flow will cause the loss of bridge clearance, and the overflow of the debris flow will cause the road to be interrupted and damaged. Many works have been carried out on the impact of debris flow on bridge piers at home and abroad. For example, in the article "Calculation of Impact Force of Large Rocks in Debris Flow Considering Elastic-Plastic Deformation" (Journal of Rock Mechanics and Engineering, 2007, 26(8):1664-16...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/23G06F30/13G06F111/10
CPCG06F30/13G06F30/23
Inventor 陈克坚刘发明游励晖徐勇付刚李明清何思明王东坡
Owner CHINA RAILWAY ERYUAN ENG GRP CO LTD
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