固化风沙土强度特性及固化机制试验研究

通过PX固化剂对库布其沙漠风沙土进行加固。对不同含水状态、不同固化剂掺量、不同养护龄期下固化风沙土的强度特性进行试验研究。试验结果表明，不同含水状态下风沙土的强度特性是不同的，相同固化剂掺量、相同养护龄期时，固化风沙土在最优含水率下的无侧限抗压强度远远大于饱和含水率下的强度。相同含水状态下固化风沙土无侧限抗压强度随固化剂掺量增加、养护龄期延长而增大，且在养护初期强度增长较快，当固化剂掺量为8 %、养护龄期为28 d时，固化风沙土强度满足国际上对固沙强度的要求。最优含水率下固化风沙土抗剪强度较风沙土有较大提高；当固化剂掺量为8 %时，固化风沙土凝聚力和内摩擦角均达到最大，此时固化风沙土抗剪强度约为风沙土的1.8倍。进而，通过扫描电镜对风沙土固化前后微观结构变化进行试验研究。研究结果表明，风沙土中掺入PX固化剂后，颗粒间由原来的弱连接变为胶结连接，解释了固化风沙土较风沙土强度得以提高、稳定性得以改善的内在原因。

Experimental studies of strength characteristics and solidified mechanism for solidified aeolian sandy soil

Aeolian sandy soil sampled from Hobq Desert was reinforced by PX soil stabilizer. A experimental studied was carried out on the strength characteristics of solidified aeolian sandy soil in different water containing states, different percentages of soil stabilizer, and different maintenance ages. Experimental results indicate that, the strength characteristics of aeolian sandy soil are different in different water containing states. The unconfined compressive strength of solidified aeolian sandy soil in optimum water content is much than the strength in saturated water content for the same stabilizer percentage and same maintenance age. The unconfined compressive strength of solidified aeolian sandy soil increases with the increase of stabilizer percentage and maintenance age in the same water containing state; and it increases quickly at the beginning of maintenance. While the stabilizer percentage is 8 %, the maintenance age is 28 d, the strength could meet requirement of international solidified sand. The shear strength of solidified aeolian sandy soil advanced obviously than aeolian, while the stabilizer percentage is 8 %, both the cohesive force and the internal friction angle reached max, and the shear strength of solidified aeolian sandy soil is 1.8 times as much as the aeolian. Furthermore, the change of the microstructure of the solidified aeolian sandy soil is studied by scanning electron microscope. Experimental results indicate that, the connection between grains changed from weak connection to adhesive bonded connection after mixed with PX stabilizer, explained the internal reasons why the solidified aeolian sandy soil's strength could increase and its stability could advance.