有限填土静止土压力系数计算方法研究

Coefficient of at-rest earth pressure from limited backfill

基于已激发内摩擦角概念,通过莫尔圆分析得到粗粒有限填土静止土压力系数K 0的计算方法,并与Jaky半无限土体静止土压力系数K 0J和有限填土主动土压力系数K a进行了对比。结果表明,当填土与基岩之间的摩擦角r等于填土内摩擦角φ时,K 0接近或小于K 0J。当δr小于φ时,K 0不仅与φ和基岩坡面倾角有关,而且与δr的大小有关,K 0可能大于也可能小于K 0J。K 0和K a均随基岩坡面倾角的增加而减小,且保持基岩坡面粗糙或分台阶开挖是减小有限填土静止土压力的有效措施。给出了有限填土静止土压力计算图。

Based on the concept of mobilized angle of internal friction, the coefficient of at-rest earth pressure from limited coarse backfill K0 is obtained after the analysis of the Molar＇s cycle. A comparison is made with Jaky＇s formula for half infinite soil mass K0j and active earth pressure from limited backfill Ka . It is found that K0 is close to or smaller than Koj, when the internal friction angle between the rock face and backfill φ is equal to that of backfill φ. K0 is not only influenced by φ and inclination of the rock face, but also by δr ; K0 may be larger or smaller than Koj, when δr is smaller than φ ; K0 and Ka decrease with the increase of the inclination of the rock slop; and K0 is larger thanKa . To make the rock face rough and to adopt bench excavation are both effective methods to reduce the at-rest earth pressure from the limited backfill. A design graph is given at the end of the paper.