Abstract Red clay is a kind of special soil which has the characteristics of high liquid plastic limit, high cohesive force, high clay mineral content, complex microstructure and so on. Mud cake at cutterhead, blocking in earth chamber and poor soil mucking are often encountered during the shield construction in red clay. Based on the EPB shield adopted in a newly built high-voltage cable tunnel on the Xiongchu avenue passing through red clay, a modified additive compounded with anionic surfactant A, nonionic surfactant B and bond-resistance additive C was developed,and the effect of soil mass conditioning was evaluated by performance test, mixing test, slump test, consistency test and liquid-plastic limit combination test, the ideal parameters for conditioning of soil mass are water content of 40%and 30% of additive injection rate. Contrast test indicates that good effect of red clay conditioning was obtained with this modified additive. The mechanism of red clay conditioning by additive was analyzed, and it is found that radical reasons for mud cake generated during shield construction are the red clay which is liable to have argillization and expansion upon meeting water and has strong glutinousness.
Abstract：
Red clay is a kind of special soil which has the characteristics of high liquid plastic limit, high cohesive force, high clay mineral content, complex microstructure and so on. Mud cake at cutterhead, blocking in earth chamber and poor soil mucking are often encountered during the shield construction in red clay. Based on the EPB shield adopted in a newly built high-voltage cable tunnel on the Xiongchu avenue passing through red clay, a modified additive compounded with anionic surfactant A, nonionic surfactant B and bond-resistance additive C was developed,and the effect of soil mass conditioning was evaluated by performance test, mixing test, slump test, consistency test and liquid-plastic limit combination test, the ideal parameters for conditioning of soil mass are water content of 40%and 30% of additive injection rate. Contrast test indicates that good effect of red clay conditioning was obtained with this modified additive. The mechanism of red clay conditioning by additive was analyzed, and it is found that radical reasons for mud cake generated during shield construction are the red clay which is liable to have argillization and expansion upon meeting water and has strong glutinousness.
CAI Binghua1 LI Zhongchao1 YU Shoulong1 LV Bingquan2 WANG Fangyan2
.Experimental Study on Red Clay Conditioning for EPB Shield Tunnelling[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(5): 218-227
2019, Vol. 56 