强风化粉砂质泥岩层坑中坑围堰渗流分析及其施工技术

Seepage Analysis and Construction Technology of Pit in Pit Cofferdam in StrongWeathered Silty Mudstone

为了减少粉砂质泥岩层坑中坑四周土体渗流,防止施工时坑壁塌方和坑底涌起,通过有限元法、现场试验和工程实践验证了无围堰、四种不同深度围堰时,坑中坑底部监测点的总孔隙水压力、流体速度和渗流量。研究发现设置围堰有效减少了总孔隙水压力、流体速度和渗流量,围堰超过坑底深度时对坑中坑坑底的总孔隙水压力、流体速度和渗流量影响不大,并提出了粉砂质泥岩层坑中坑围堰施工新方法,总结了其施工技术。结果表明,粉砂质泥岩层坑中坑围堰施工技术防渗效果明显,值得推广,且深度以大于坑中坑深度0.5m为宜。

In order to reduce the seepage of the soil around the pit in Strong Weathered silty mudstone,prevent the collapse of the pit wall and the bottom of the pit during construction;through finite element method,field test and engineering practice verified that there were no cofferdams and four different depth cofferdams in the pit in pit.Total pore water pressure,fluid velocity,and seepage at the bottom of the pit monitoring point.It finds that the cofferdam is effective in reducing the total pore water pressure,fluid velocity and seepage flow.When the cofferdam exceeds the depth of the pit,it has little effect on the total pore water pressure,fluid velocity and seepage flow at the bottom of the pit.A new method for the construction of pit cofferdams in strong weatheredsilty mudstone pits is summarized and its construction techniques were summarized.The results show that it is obvious about the anti-seepage effect of the construction technology of the pit cofferdam in strong weathered silty mudstone pit,and it is worthy of promotion,and the suitable depth is greater than the pit depth of 0.50m.