不同水泥掺量下非饱和固化淤泥力学特性试验研究

Experimental study of mechanical properties of unsaturated solidified silt with different cement contents

为明晰非饱和固化淤泥的强度特性,通过不同基质吸力、净围压下的三轴固结排水试验、无侧限抗压强度试验,探讨了水泥掺量、基质吸力和净围压对非饱和固化淤泥强度特性的影响.试验结果表明:固化淤泥的土-水特征曲线在基质吸力小于进气值时饱和度变化并不明显,而基质吸力大于进气值时,随着基质吸力的增大,固化淤泥的饱和度降低,低水泥掺量固化淤泥的土-水特征曲线位于高水泥掺量固化淤泥土-水特征曲线的下方;水泥掺量100 kg/m^3固化淤泥的应力-应变曲线表现为应变硬化,剪切时表现为体缩,而水泥掺量200、300 kg/m^3固化淤泥的应力-应变曲线均表现为应变软化,水泥掺量越高、净围压越小,应变软化趋势越明显.非饱和固化淤泥的无侧限抗压强度和抗剪强度与水泥掺量和基质吸力有关,水泥掺量越高、基质吸力越大,无侧限抗压强度和抗剪强度越大.不同水泥掺量和基质吸力条件下抗剪强度和无侧限抗压强度之间存在良好的线性关系.

In order to clarify the strength characteristics of unsaturated solidified silt, the influence of cement content, matric suction and net confining pressure on the strength characteristics of unsaturated solidified silt is discussed by performing consolidated drained triaxial test and unconfined compressive strength test under different matric suctions and net confining pressures. Test results show that for the soil-water characteristic curve of solidified silt, when the matric suction is lower than the air entry value, matric suction has insignificant influence on the degree of saturation, whereas, when the matric suction is higher than the air entry value, the degree of saturation decreases with the increase of matric suction. The soil-water characteristic curve of solidified silt with low cement content is located below the soil-water characteristic curve of solidified silt with high cement content. The stress-strain curve of solidified silt with cement content of 100 kg/m^3 shows strain hardening and the volume change exhibits only compressive behavior. However, the stress-strain curves of solidified silt with cement contents of 200 kg/m^3 and 300 kg/m^3 show strain softening. The higher the cement content, the smaller the net confining pressure, the more obvious the strain softening trend. The unconfined compressive strength and shear strength of unsaturated solidified silt are related to the cement content and matric suction. The unconfined compressive strength and shear strength increase with the increase of cement content and matric suction. A linear relationship is found between the shear strength and unconfined compressive strength under different cement contents and matric suctions.