福州扰动软土水泥改良性能试验研究

Experimental Study on Improvement Performance of Cement in Disturbed Soft Soil in Fuzhou

为严格控制邻近既有地铁隧道进行的钻孔灌注桩施工作业对地层扰动的影响,研究了水泥对扰动软土性能的改良效果。水泥掺量、剪切速率对改良软土剪切性能的试验结果表明:与原状、重塑软土类似,水泥改性土应变软化与剪切速率有关,存在临界值。剪切速率增加导致粘聚力先增大后降低再增大,而内摩擦角加速降低。

In order to strictly controll the influence of the construction of bored piles adjacent to the existing subway tunnel on the ground disturbance,the improvement effect of cement on the performance of disturbed soft soil was studied.The experimental results of cement content and shear rate on the shear performance of improved soft soil showed that:similar to undisturbed and remolded soft soil,the strain softening of cement modified soil was related to the shear rate,and there was a critical value.The increase of shear rate led to the increase of cohesion first,then decreased and then increased,while the internal friction angle decreased rapidly.