超厚流塑状冲填土地层放坡支护技术分析

Analysis on Technology of Gravel Support for Super-thick Flow Plastic-filled Soil

南方软土地区土质软弱,土体自稳能力差,特别是在超厚流塑状冲填土的地层,土体完全没有自稳能力,放坡施工难度大。常采用围护桩或地连墙加内支撑的支护形式,造价高,施工速度慢,工期长,特别对于施工场地比较充裕的工程,经济上不合理。结合苏州某地下空间工程的施工案例,针对超厚流塑状冲填土层的不良地质条件,通过采用拉森钢板桩隔断放坡施工段与周边流塑状冲填土层间的联系,刷坡前打设圆木桩提前改良地层,合理划分刷坡长度,及时进行网喷混凝土支护和土钉墙加固等多种常规边坡支护方式的组合应用,成功解决了超厚流塑状冲填土层放坡施工无法成坡的问题,获得良好的支护效果和经济效益。为类似地质条件下进行放坡开挖支护设计与施工,提供可以借鉴与参考的工程实例。

In the southern soft soil area,soil is weak and the soil self-stabilizing ability is poor,especially in the strata with thick and thick flow plastic-filled soil. The soil has no self-stabilizing ability and the slope construction is difficult. Often used to support the pile or ground wall plus support within the support form, high cost, construction speed is slow, long duration, especially for the construction site more abundant projects, economically unreasonable. In this paper, according to the construction case of a subterranean space project in Suzhou, the relationship between the construction section of the grading section and the surrounding flow plastic punching soil layer is adopted by using the Larsen steel sheet pile for the poor geological conditions of the super-thick flow plastic-,the slope of the slope before playing round piles in advance to improve the formation of a reasonable division of the length of the brush slope, the timely implementation of the network spray concrete support and soil nailing wall reinforcement and other conventional slope support mode combination of applications, successfully resolved the super-thick plastic castings can not be ramped slope construction problems, access to good support and economic benefits. For similar geological conditions for grading excavation support design and construction, to provide reference and reference to the engineering examples.