改性加固土抗压/粘聚/内摩擦等性能测试及基坑应用验证分析

The property test of modified reinforced soil such as compression resistance cohesion and internal friction and the application verification analysis of foundation pit

水泥加固土技术在我国沿江、沿湖、沿海地区的城市建设中得到了广泛的应用。基于以春申湖路快速化改造工程5号节点基坑为研究背景,开展了水泥土密度、抗压强度、粘聚力和内摩擦角等物理力学性能测试,在此基础上建立了实际工程水泥土加固应用数值模型,分析了基坑土体及周边隧道在加固前后的位移变化规律。研究结果表明,水泥土搅拌桩的密度、无侧限抗压强度、弹性模量、粘聚力、内摩擦角均随水泥掺量的增大而呈线性增大。采用3轴水泥土搅拌桩以及MJS工法对春申湖路快速化改造工程5号节点基坑进行组合加固后,基底最大隆起值减小79.2%,4号线盾构隧道管片衬砌最大竖向位移和水平位移则分别减小79.7%和68.3%。

Cement reinforced soil technology has been widely used in urban construction along rivers, lakes and coastal areas in China.Based on this, the foundation pit of No.5 node of Chunshenhu Road rapid reconstruction project is taken as the research background in this paper, and the density, unconfined compressive strength, elastic modulus, cohesion and internal friction angle of soil-cement were tested.Based on these, a numerical model for the application of cement-soil reinforcement in practical engineering is established, and the displacement change law of the foundation pit soil and surrounding tunnels before and after reinforcement is analyzed.The results show that the density, compressive strength, cohesion and internal friction Angle of soil-cement mixing pile increase with the increase of cement content.The maximum uplift of the foundation is reduced by 79.2%,the maximum vertical displacement and horizontal displacement of the shield tunnel segment lining of Line 4 are reduced by 79.7% and 68.3% respectively after the combined reinforcement of the foundation pit at node 5 of Chunshenhu Road rapid reconstruction project by using triaxial cement soil mixing pile and MJS construction method.