软土地基注浆扩散过程数值模拟研究

廊沧高速公路K132+177～K132+258软土地基主要由低液限中、高压缩性黏土层组成,属于滨海沉积类型,采用静力注浆方法进行了加固处理,并在现场分别对全孔一次性和自上而下分段式注浆施工方式进行了试验及室内研究。基于该路段软土地基地基物理力学性质和注浆试验地表变形观测资料,利用FLAC3D软件对该软土地基在不同注浆方式(全孔一次性注浆、自上而下分段式注浆)和在0.5、1.0、2.0 MPa注浆压力作用下浆液在土层中的扩散过程进行了分析。其结果表明,在相同注浆压力作用下,自上而下分段式注浆效果比全孔一次性注浆效果好,而注浆压力的增大对浆液在土层中的扩散是有利的,但压力过大会导致地面冒浆,应根据现场实际情况选择合理的注浆压力。

Numerical simulation study of grouting diffusion process in soft soil foundation

The soft soil foundation of the section K132+177～+258 of Langfang-Cangzhou Expressway in Hebei province is mainly composed of low liquid limit, middle-high compressibility clay layer, belonging to the type of coastal sedimentary deposit, which is treated mainly adopting static grouting. The test and laboratory studies respectively for grouting construction method of whole pore disposable and top-down segmentation tabulator in field are taken. On the basis of physical and mechanical properties of soft soil foundation and observation data of grouting test surface deformation amount, the diffusion processes of slurry in different grouting construction methods (whole pore disposable and top-down segmentation tabulator grouting) and different grouting pressures (0.5, 1.0 MPa and 2.0 MPa) are studied by using FLAC3D. The results show that the grouting effect of top-down segmentation tabulator grouting is better than whole pore disposable grouting in the same grouting pressure; and the increasing pressure is beneficial to grouting diffusion. But it would result flow-up of grout with the higher pressure. Therefore, we should choose reasonable grouting pressure according to the practical site situation