深厚软土水泥搅拌桩复合地基沉降分析及控制

深层水泥搅拌桩是处理深厚软土地基的有效方法。本文结合温州地区典型深厚软土 ,首先分析了采用水泥搅拌桩加固的4～ 8层建筑物地基的长期沉降观测结果 ,并用传统的方法进行了沉降计算 ,发现计算结果是实测结果的 3倍左右。然后 ,试验研究了典型温州软土的结构性 ,得出主要压缩层的土体结构屈服应力比在 1 7～ 2 5范围内 ,发现当下卧层的附加应力σz 与有效自重应力σz0 ′之和小于土体结构屈服应力σsy 时 ,建筑物沉降将得到有效控制。最后 ,在前人研究工作的基础上 ,提出考虑软土结构性的沉降计算方法 ,考虑土的结构性对下卧层沉降的影响 ,对 12幢不同层数的建筑物进行了沉降计算 ,计算结果与实测结果相当一致。

Analysis and control of the settlement in thick soft clay ground reinforced by deep mixing cement piles

Deep mixing cement pile is a effective method to reinforce thick soft clay ground.In allusion to the typical thick soft clay in Wenzhou,this paper analyses the chronically monitored settlement of 4～8 floor building's composite foundation reinforced by deep mixing cement piles,and calculates the settlement with traditional method,and find that calculated settlement is 2 times greater than monitored value.The structure characteristics typical soft clay is studied through experimentation,and the yield stress ratio of soil structure is found in the range of 1.7～2.5,and the settlement of building will be effectively controlled when the sum of superimposed stress and effective self-weight stress is less than yield stress of soil structure in under-lying soft layer.Finally, referring to other researchers' studies and in view of the influence of soil structure characteristics to the settlement of under-lying soft layer, a new settlement calculation method has been put forward.With this method,settlement of 12 buildings are calculated and the calculated results are very close to the monitored results.