上覆压力对湛江组结构性黏土触变性的影响机制

上覆压力对湛江组结构性黏土触变性具有显著的影响。上覆压力大小不同，导致湛江组结构性黏土触变性强弱不同，使得湛江组结构性黏土地基强度恢复程度存在差异。研究上覆压力对湛江组结构性黏土触变性的影响机制，有助于深入了解上覆压力造成地基强度恢复程度不同的本质原因。在不同上覆压力作用下对扰动后的湛江组结构性黏土在不同静置龄期进行直接剪切试验和扫描电镜试验，探究土体的触变强度比率随上覆压力变化规律以及土体的微观结构演变规律，从宏微观角度阐明上覆压力对湛江组结构性黏土触变性影响机制。结果表明：在相同上覆压力作用下，随着静置龄期增长，土体抗剪强度和触变强度比率增大，触变强度比率与静置龄期呈乘幂函数关系，土体的概率熵和颗粒分布分维数均下降，土颗粒往团聚化发展、排列定向性逐渐加强：静置龄期相同时，随着上覆压力的增大，土体抗剪强度增大，但随着静置龄期的增长，土体触变强度比率减小，触变强度比率与上覆压力呈一次函数关系，土体概率熵和颗粒分布分维数下降的幅度减小，土颗粒往团聚化发展和排列定向性增长的速率变慢。

Influence mechanism of overburden pressure on thixotropy of structural clay in Zhanjiang formation

The overburden pressure has a important influence on the thixotropy of structural clay of the Zhanjiang formation. The different overburden pressures lead to different strength of thixotropy of the structural clay of the Zhanjiang formation, resulting in differences in the degree of foundation strength recovery of the structural clay of the Zhanjiang formation. Studying the influence mechanism of overburden pressure on the thixotropy of structural clay in the Zhanjiang Formation will help to understand the essential reasons for the different degrees of foundation strength recovery caused by overburden pressure. The direct shear test and scanning electron microscope test were carried out on the structural clay of Zhanjiang formation under different overburden pressure after disturbance at different resting stages to explore the variation law of soil thixotropic strength ratio with overburden pressure and the evolution law of soil microstructure, the influence mechanism of overburden pressure on the thixotropy of structural clays in Zhanjiang formation was discussed from macro and micro perspectives. The results show that under the same overburden pressure, with the increase of the resting stages, the shear strength and thixotropic strength ratio of the soil increase, the thixotropic strength ratio and the resting stages show a power function relationship, the probability entropy of the soil and the fractal dimension of particle distribution decrease, the soil particles tend to agglomerate, and the orientation of the arrangement is gradually strengthened: when the resting stages are the same, the shear strength of the soil increases with the increase of the overburden pressure, However, with the increase of the resting stages, the thixotropic strength ratio of the soil decreases. The thixotropic strength ratio is a function of the overburden pressure. The decrease range of soil probabilistic entropy and fractal dimension of particle distribution decreases, and the rate of the development of the soil particles toward agglomeration and the growth of the orientation of the soil particles becomes slower.