CN-121980790-A - Non-limiting earthquake active soil pressure calculation method for unsaturated soil behind retaining wall

CN121980790ACN 121980790 ACN121980790 ACN 121980790ACN-121980790-A

Abstract

The invention discloses a method for calculating the non-limit earthquake active soil pressure of unsaturated soil behind a retaining wall, which relates to the technical field of retaining wall engineering and comprises the following steps of determining the assumed condition of the non-limit earthquake active soil pressure of the unsaturated soil behind the retaining wall; the method comprises the steps of obtaining soil body non-ultimate strength parameters based on a unified strength theory, determining unsaturated soil pressure calculation parameters in an non-ultimate state, establishing a non-ultimate earthquake active soil pressure calculation model of unsaturated soil behind a retaining wall, and calculating horizontal soil pressure resultant force acting on retaining wall strength based on the non-ultimate earthquake active soil pressure calculation model of the unsaturated soil behind the retaining wall. The method and the device are used for solving the problem that in the prior art, the effective calculation of the earthquake active soil pressure expansion of the unsaturated soil is difficult to realize under the non-limit state of the soil mass, and achieving the purpose of effectively calculating the non-limit earthquake active soil pressure of the unsaturated soil behind the retaining wall and providing reference and support for engineering construction.

Inventors

ZHANG SHUAI
ZHAI YONG
LI JIEYONG
LIU YANLONG
XIONG ZHIGANG
XI CHENG
LIU CHENKUN
DONG CHAO
ZHANG WENLI
Song Aiqiang

Assignees

中铁二十三局集团有限公司

Dates

Publication Date: 20260505
Application Date: 20260122

Claims (10)

1. The method for calculating the non-limiting earthquake active soil pressure of the unsaturated soil behind the retaining wall is characterized by comprising the following steps of: S1, determining a presumption condition of non-ultimate earthquake active soil pressure of unsaturated soil behind a retaining wall; s2, obtaining non-ultimate strength parameters of the soil body based on a unified strength theory; S3, determining an unsaturated soil pressure calculation parameter in a non-limiting state; S4, establishing a non-limiting earthquake active soil pressure calculation model of unsaturated soil behind the retaining wall; s5, calculating the resultant force of horizontal soil pressure acting on the retaining wall strength based on the non-limiting earthquake active soil pressure calculation model of the unsaturated soil behind the retaining wall.
2. The method for calculating the non-limiting earthquake active soil pressure of the unsaturated soil behind the retaining wall according to claim 1, wherein in the step S1, the assumed condition is that the retaining wall is vertical and the surface of the soil behind the retaining wall is horizontal, the soil behind the retaining wall is divided into a plurality of soil strips from the longitudinal direction, the large and small principal stresses of the soil strips deflect, so that one end of the soil strip close to the retaining wall is kept fixed, and one end of the soil strip far from the retaining wall deflects downwards towards the direction close to the retaining wall to generate a soil arch.
3. The method for calculating the non-limiting earthquake active soil pressure of the unsaturated soil behind the retaining wall according to claim 2, wherein in the step S2, the soil non-limiting strength parameter comprises an effective internal friction angle based on a uniform strength theory and considering the non-limiting state of the soil behind the retaining wall Effective friction angle of wall soil contact surface based on unified strength theory and considering non-limiting state of soil body behind retaining wall 。
4. The method for calculating the non-limiting seismic active soil pressure of the unsaturated soil behind the retaining wall according to claim 3, wherein the effective internal friction angle based on the unified strength theory and considering the non-limiting state of the soil behind the retaining wall The method comprises the following steps: Effective internal friction angle of non-cohesive soil is measured by triaxial consolidation drainage test or consolidation non-drainage pore pressure test ; Calculating an effective internal friction angle based on the unified strength theory and considering the non-limiting state of the soil body behind the retaining wall by the following formula : ; ; Wherein eta is a proportionality coefficient, eta=S (z)/S, S (z) is the actual displacement of the soil body behind the retaining wall, S is the maximum displacement required by the soil body behind the retaining wall from a static state to a limit state, and R f is a destruction ratio; B is an intermediate principal stress coefficient, b is more than or equal to 0 and less than or equal to 1;m and is a stress coefficient, and sigma 2 =m*[(σ 1 +σ 3 )/2];σ 1 、σ 2 、σ 3 is respectively the maximum principal stress, the intermediate principal stress and the minimum principal stress.
5. The method for calculating the non-limiting earthquake active soil pressure of the unsaturated soil behind the retaining wall according to claim 4, wherein the effective friction angle of the wall soil contact surface based on the unified strength theory and considering the non-limiting state of the soil behind the retaining wall Calculated by the following formula: 。
6. The method for calculating the non-limiting seismic active soil pressure of the unsaturated soil behind the retaining wall according to claim 3, wherein in the step S3, the non-limiting state unsaturated soil pressure calculation parameters include: maximum principal stress inclination angle of soil strip near one end of retaining wall ; Maximum principal stress inclination angle after soil strip is deflected away from one end of retaining wall ; Wall rear soil body potential fracture surface inclination angle based on unified strength theory and considering non-limiting state of soil body behind retaining wall ; The horizontal soil pressure coefficient K wall on the retaining wall; the average shear stress coefficient K hss of the soil body behind the wall.
7. The method for calculating the non-limiting seismic active soil pressure of unsaturated soil behind a retaining wall according to claim 6, 、、 Calculated by the following formula: wherein lambda is the seismic angle, s is the calculation parameter.
8. The method for calculating the non-limiting seismic active soil pressure of unsaturated soil behind a retaining wall according to claim 6, wherein K wall 、K hss is calculated by the following formula: ; 。
9. the method for calculating the non-limiting earthquake active soil pressure of unsaturated soil behind a retaining wall according to claim 6, wherein in step S5, the resultant horizontal soil pressure force is calculated by the following formula: ; wherein P Resultant force of soil pressure is the resultant force of horizontal soil pressure, H is the height of the retaining wall, z is the thickness of soil above the soil strip, and A 1 、A 2 、A 3 、A 4 、A 5 and C are both intermediate coefficients.
10. The method for calculating the non-limiting seismic active soil pressure of unsaturated soil behind a retaining wall according to claim 9, wherein each intermediate coefficient is calculated by the following formula: ; ; ; ; ; ; wherein gamma is the soil weight behind the retaining wall, k v is the vertical seismic coefficient, k h is the horizontal seismic coefficient, u a is pore air pressure, u w is pore water pressure, (u a -u w ) is matrix suction force, delta b is the wall soil contact surface friction angle, and phi b is the matrix suction force angle.

Description

Non-limiting earthquake active soil pressure calculation method for unsaturated soil behind retaining wall Technical Field The invention relates to the technical field of retaining wall engineering, in particular to a non-limiting earthquake active soil pressure calculation method for unsaturated soil behind a retaining wall. Background Retaining wall structures have been widely used in the construction of construction works, road traffic, and hydraulic engineering. A large number of engineering cases show that the backfill soil body of the retaining wall under the earthquake condition vibrates reciprocally, the dynamic soil pressure is increased sharply, and the retaining wall is easy to be damaged by wall overturning, wall sliding, integral instability and the like. Based on the actual situation of construction sites, unsaturated soil is often adopted as backfill soil behind the retaining wall after the retaining wall is constructed, the physical and mechanical properties of the unsaturated soil are obviously different from those of common dry soil, and the shear strength of the unsaturated soil consists of effective stress strength and matrix suction strength. The soil pressure of unsaturated soil acting on the retaining wall is dynamically adjusted along with the change of the water content. The matrix suction force is large and the soil pressure is smaller during drought, the matrix suction force is lost and the soil pressure is close to the saturated soil pressure after rainfall, so that overload damage to the retaining wall is easy to occur. The displacement of the earth body behind the wall does not reach the displacement quantity which enables the earth body behind the wall to be in a limit state under most conditions after the construction of the retaining wall engineering is finished or during the operation, and the non-limit state of the earth body needs to be considered in the process of calculating the earthquake active earth pressure behind the wall. In the prior art, under the condition of considering the non-limit state of the soil body, the effective calculation of the earthquake active soil pressure expansion of the unsaturated soil is difficult, and the reference and the support are difficult to provide for engineering construction. Therefore, in combination with the actual demands of the retaining wall in engineering construction, a method for calculating the non-limiting earthquake active soil pressure of the unsaturated soil behind the retaining wall is urgently needed. Disclosure of Invention The invention provides a method for calculating the non-limit earthquake active soil pressure of unsaturated soil behind a retaining wall, which aims to solve the problem that the effective calculation of the earthquake active soil pressure expansion of the unsaturated soil is difficult to realize under the non-limit state of considering soil in the prior art, and the purposes of effectively calculating the non-limit earthquake active soil pressure of the unsaturated soil behind the retaining wall and providing reference and support for engineering construction are realized. The invention is realized by the following technical scheme: the method for calculating the non-limiting earthquake active soil pressure of the unsaturated soil behind the retaining wall comprises the following steps: S1, determining a presumption condition of non-ultimate earthquake active soil pressure of unsaturated soil behind a retaining wall; s2, obtaining non-ultimate strength parameters of the soil body based on a unified strength theory; S3, determining an unsaturated soil pressure calculation parameter in a non-limiting state; S4, establishing a non-limiting earthquake active soil pressure calculation model of unsaturated soil behind the retaining wall; s5, calculating the resultant force of horizontal soil pressure acting on the retaining wall strength based on the non-limiting earthquake active soil pressure calculation model of the unsaturated soil behind the retaining wall. Aiming at the problem that in the prior art, effective calculation is difficult to realize aiming at the earthquake active soil pressure expansion of unsaturated soil in a non-limit state of a soil body, the invention provides a non-limit earthquake active soil pressure calculation method of unsaturated soil behind a retaining wall, which comprises the steps of firstly determining the assumed condition of the non-limit earthquake active soil pressure of the unsaturated soil behind the retaining wall, and then introducing a unified strength theory on the basis of the assumed condition to obtain soil body non-limit strength parameters under the unified strength theory; and then considering the unsaturated state of the soil body, determining the pressure calculation parameters of the unsaturated soil in the non-limiting state, and then establishing a non-limiting earthquake active soil pressure calculation model of the unsaturated soil behind t