Analysis And Application Study Of Corner Effect For Deep Excavation Based On Soil Arching Effect

The foundation pit engineering is not a problem of plane in two dimension, it hasspatial structure. When we calculate the soil pressure of foundation pit side wall, weoften adopt classic theory of earth pressure, but it does not reflect the real situationof foundation pit under stress. Corner effect is universal in foundation pit engineering.The most important effect factors of corner effect are support structure and soil archeffect. This article adopts horizontal differentiation to analysis corner effect and usesFLAC3D to imitate support structure, and make sure the effect range of slip wall. Ithas an important practical significance to improve the security and stability of thesupporting structure.Adopt FLAC3D method to simulate monolayer sand, and use the results of theground settlement and boundary, the displacement of foundation pit and the stresscloud in x, xy, z direction to analysis the influence of corner effect, and analysis theeffect that the range of ground settlement impact on slip surface dip and soil influencedepth.FLAC3D adopts Mole-Kulun constitutive model to imitate the soil, and uses thetheory of Kulun soil pressure to calculate the slip surface dip on the premise of usinghorizontal differentiation. It accords with the requirement of horizontal differentiationmethod when we use FLA3D to imitate the earth surface settlement and range.This article contra poses the problem of classic soil pressures theory and useshorizontal differentiation to analysis soil arch effect. There are two conditions to formsoil arch effect, first is the relative asymmetry displacement of soil, second is archangle to support soil arch. The soil arch effect is due to the soil no uniformdisplacement. The soil effect changes the stress state in medium, and arouses the stress to redistribute. It send the stress on the arch and behind the arch to the foot ofarch and steady medium around soil. It reaches the balance and achieves the stressredistribute through the soil shear strength.The soil arch effect changes the stress state in medium, and around the stress toredistribute. It is the trace of minor principal stress. It gets the expression of soilpressure distribution and point of action of soil resultant force through calculating theminor principal stress.This article suppose that the stress trace of soil arch effect is parabola. The frictionangle between foundation pit side wall and soil is the first arch angle for supporting,and the slip surface by the relative slip of soil is the second arch angle of supporting.We calculate formula of the soil pressure distribution using horizontal differentialmethod under initiative limit equilibrium. We analysis the friction between soil andfoundation pit side wall influence on the soil effect and calculate the soil pressuredistribution by the changing of slip surface dip or the influence depth changing ofslide soil when close the corner from the middle of pit.This article get the soil pressure formula through combining the result of FLAC3Dimitating and horizontal differential method. We summarize the relation of foundationpit side wall pressure distribution and displacement and the earth settlement and rangewhen the side wall pressure closes the pit corner from middle of pit, and get theinfluence of corner effect to the foundation pit side wall.