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A Calculation Method for Earth Pressure of Retaining Wall in Soft Soil Area

A calculation method and retaining wall technology, applied in construction, artificial island, infrastructure engineering, etc., can solve complex, inaccurate and inconvenient active earth pressure problems, and achieve the effect of simple flow field

Active Publication Date: 2019-03-08
CHINA RAILWAY NO 2 ENG GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the seepage condition is not considered in the prior art, it is extremely inaccurate and inconvenient to calculate the active earth pressure caused by the seepage. At the same time, when calculating the flow field reaching the permeable surface, it is necessary to draw the flow network, which is very complicated

Method used

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  • A Calculation Method for Earth Pressure of Retaining Wall in Soft Soil Area
  • A Calculation Method for Earth Pressure of Retaining Wall in Soft Soil Area
  • A Calculation Method for Earth Pressure of Retaining Wall in Soft Soil Area

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Embodiment 1

[0057] The structure of the vertical retaining wall considering the seepage conditions is such as figure 1 As shown, since the wall is permeable along the interface between the soil body 2 and the retaining wall 1, all the water reaching the interface can be drained. The soil body is non-viscous and fully saturated under the ground. This condition may occur when continuous heavy rain falls. This condition is critical when the active earth pressure reaches its maximum value. The bottom of the soil layer is an impermeable layer, so all water reaching the retaining soil body will follow the soil and The interface of the structure flows away at a certain time.

[0058] Establish a closed-form analytical solution of water seepage in the soil, and then use this solution in the Coulomb equation. According to the equation, set the wall displacement enough to make the soil in the active state. There will be a plane failure surface. In this way, the Coulomb-like coefficient of active earth...

Embodiment 2

[0090] Such as Figure 4 As shown, it is assumed that the interface between soil body 2 and retaining wall 1 is completely smooth, and the acting direction of earth pressure is horizontal. When the displacement of retaining wall 1 is sufficient to cause the shear strength of soil body 2 (active state) Change, a failure surface (set as a plane) will be formed. The soil wedge 3 formed by the failure surface is regarded as a rigid body, and the force acting on its boundary is shown in the analysis in the figure.

[0091] Such as Figure 4 In, the weight of the soil wedge is shown in equation 13;

[0092] Formula 13: Where γ sat Is the saturation weight of the soil, H is the height of the wall, and a=cotθ represents the slope of the failure surface.

[0093] Pa is the active earth pressure, N is the normal effective stress, and T is the tangential force acting on the failure surface. Pore ​​water pressure U is the resultant force of pore water pressure acting on the failure surface, U...

Embodiment 3

[0108] Equation 22 shows that the active earth pressure is linearly distributed along the wall, but this is not correct. In order to obtain the correct earth pressure distribution, certain assumptions must be made, such as Figure 7 As shown, when the soil body 2 is in the active state, all the soil in the critical soil wedge 3 are in a plastic equilibrium state, and then the Figure 7 As shown in the analysis.

[0109] The active earth pressure coefficient used to calculate the partial pressure of this part is different from the coefficient obtained in the previous area. The reason for the difference is that the seepage conditions in the local pressure soil wedge are different from the seepage conditions in the full-length area, because they have different distances from the impervious layer at the bottom of the soil layer.

[0110] In the case of local earth pressure, the gravity and pore water pressure along the surface of the soil wedge are respectively W * And U * , Such as fo...

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Abstract

The invention relates to the technical field of civil engineering, and discloses a method for calculating an earth pressure of an earth retaining wall in a weak soil region. The method comprises the following steps: establishing a closed-form analytic solution of water seepage flow in a soil body, applying the analytic solution to a Coulomb-form equation, setting a failure surface that is formed by means of the equation when the soil body is in an active state is a plane, determining a total water head h(x, z) in a seepage area under a seepage condition, obtaining total water carrying capacity Q reaching a drainage system by a horizontal component upsilonx of seepage velocity , and calculating an active earth pressure and an active earth pressure coefficient Kas of an earth wedge body when seepage is only present at the local part of the soil body. By adopting the earth pressure calculating method disclosed by the invention, an underground water penetration function is introduced into the calculation process to obtain a general solution of the active earth pressure on a vertical surface of the earth retaining wall, so that the active earth pressure caused by seepage can be calculated and taken into consideration conveniently and accurately, and meanwhile, according to a final solution of h(x, z) that is determined under the seepage condition, the calculation of a flow field reaching a pervious surface is simplified, and a flow net can be drawn directly.

Description

Technical field [0001] The invention relates to the technical field of civil engineering, in particular to a method for calculating the pressure of a retaining wall in a soft soil area. Background technique [0002] In soil mechanics, calculating the soil pressure acting on the structure by the soil is an ancient and important subject. The theory of earth pressure on retaining walls was first proposed by French engineer Coulomb and is called Coulomb's earth pressure theory. Then, the British professor Rankine established the Rankine earth pressure theory. These two earth pressure theories have the advantages of simple calculation and clear mechanical concepts, so they have been widely used in civil engineering and become a classic of earth pressure on retaining walls. theory. [0003] Earth pressure is the result of the interaction between soil and structure, and the interaction between soil and structure is the key to analyzing the problem of earth pressure. During the excavati...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E02D29/02
CPCE02D29/02
Inventor 余雨夏李朝刚王元
Owner CHINA RAILWAY NO 2 ENG GRP CO LTD
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