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软土一般具有蠕变特性,蠕变在微观上表现为土颗粒与孔隙的变化。为了解长期变形内在机制,对天津滨海吹填软土原状土与重塑土进行了固结不排水三轴蠕变试验。在围压为75 kPa、偏应力为10 kPa情况下开展多组平行试验,选取蠕变过程中多个时间点的试样进行微观结构测试,提取了颗粒与孔隙变化参数,研究蠕变过程中微结构变化规律。研究结果表明:在文中所受荷载条件长期作用下,颗粒与孔隙定向性明显;平均孔径及平均孔隙体积呈逐渐减小趋势;结构性原状土比表面积逐渐增大,重塑土则呈减小趋势;结构性原状土颗粒与孔隙分数维呈减小趋势,但重塑土呈相反趋势。
Soft soil generally has creep characteristics, and creep shows microscopically the change of soil particles and pores. In order to understand the inherent mechanism of long-term deformation, a test of undrained triaxial creep of consolidated undrained soil was carried out on the original coastal plain filled with soft soil in Tianjin. Under the conditions of confining pressure of 75 kPa and deviatoric stress of 10 kPa, a series of parallel experiments were carried out. The microstructures of the samples were selected at different time points during the creep process. Particle and pore parameters were extracted to study the creep process Microstructure changes. The results show that under the long-term load conditions, the orientation of particles and pores is obvious, the average pore size and average pore volume decrease gradually, the specific surface area of structural intact soil increases gradually and the remolded soil decreases Trend; structural undisturbed soil particles and pore fractal dimension tends to decrease, but the plastic soil showed the opposite trend.