浅层软黏土注浆加固方法研究

Study of grouting strengthen method on shallow soft clay

注浆一直是处理不良地质的有效方法,取得了良好的治理效果。针对浅层软黏土注浆管路难以固定;注浆压力上不去,很难劈裂黏土体,导致浆液进不到黏土中的特殊性,提出了一种模袋袖阀管相结合的注浆工艺,利用水泥基速凝材料凝结固化时间较长的特点,研究针对浆液可泵性,调节速凝材料与水泥浆配比,控制注浆压力的注浆方法,制定浅层软黏土注浆加固方案。研究结果应用于南京上元门车站基坑涌水注浆堵水工程,解决了浅层软黏土体涌水问题,实现了围岩稳定性控制。研究成果具有一定的理论和实践意义,对类似工程具有参考价值。

The grouting has been an effective method in treating unfavorable geological conditions, which has received remarka- ble results. However, in the shallow deposited cohesive soils, due to the difficulties in fixing the grouting sleeve, the soil layer is hard to be split and the grouting fluid cannot penetrate into the cohesive soils as a result of the low grouting pressure. A new grouting procedure, which uses the sleeve-valve pipe inserted into the geotextile tube, is introduced to resolve this difficulty. The new procedure utilizes character of the longer initial hardening time of the cement based grouting slurry, adjusts the ratio of the fast hardening additives to the cement slurry and controls the grouting pressure to achieve the optimized pumping results. This procedure has been applied to the groundwater cut-off in the deep excavation of Shangyuanmen Station in Nanjing. The shallow deposited cohesive soil groundwater cut-off is achieved by the new grouting method and it has a significant contribution to the stability of the deep excavation.