浆液扩散模式对地层附加土压力影响试验研究

Experimental study on influence of slurry diffusion mode on additional earth pressure of formation

针对现有盾构隧道变形恢复注浆过程中地层附加土压力形成影响因素不明的问题,分别采用不同含水量浆液和注浆方式开展了注浆单元体试验,并对注浆产生的附加土压力及浆液扩散形态进行了分析.试验结果表明:当采用直接法注浆时,浆液的含水量对其扩散模式影响显著,进而影响注浆导致的地层附加土压力;浆液的含水量越低,其流动性越差,注入地层时发生跑浆的可能性越小,因此越有利于地层注浆附加土压力的形成;当采用囊袋法注浆时,地层中的附加土压力增长平稳,注入相同体积浆液后总体产生的地层附加土压力更大.在满足浆液在注浆管内流动性与可注性的条件下,盾构隧道变形恢复注浆过程中建议降低浆液的含水量,以提高浆液稠度,并考虑采用囊袋法进行注浆.

In response to the problem of unclear factors affecting the formation of additional soil pressure during the deformation recovery grouting process of existing shield tunnels,grouting unit tests were conducted using different water content slurry and grouting methods,and the additional soil pressure and slurry diffusion morphology generated by grouting were analyzed.Experimental results show that when direct grouting is used,the water content of the slurry has a significant impact on its diffusion mode,which in turn affects the additional soil pressure caused by grouting in the formation.The lower the water content of the slurry,the poorer its fluidity,and the lower the possibility of slurry running during injection into the formation,which is more conducive to the formation of additional soil pressure during formation grouting.When using the bag grouting method,the additional soil pressure in the formation increases steadily,and the overall additional soil pressure generated by injecting the same volume of grout is greater.Under the conditions of meeting the fluidity and injectability of the slurry inside the grouting pipe,it is recommended to reduce the water content of the slurry during the deformation recovery grouting process of shield tunnels to improve the viscosity of the slurry,and consider using the bag method for grouting.