膨胀土强度影响因素与规律的试验研究

针对同一种膨胀土，通过直剪试验和三轴试验研究了土体由无裂隙天然非饱和状态到无裂隙饱和状态再到裂隙充分发展的饱和状态的过程中强度的影响因素和变化规律。试验结果表明，含水率、密度以及裂隙是影响膨胀土强度的三个因素，其中含水率和裂隙对强度的影响较大，密度对强度的影响较小。膨胀土强度指标的确定应考虑裂隙的开展。建议用试样做5次干湿循环后的强度指标作为膨胀土裂隙发育区的强度指标。通过膨胀土残余强度试验分析表明，所得指标与裂隙充分发展的膨胀土强度指标是接近的，故也可用其作为裂隙发育区的强度指标近似值。

Experimental study of factors influencing expansive soil strength

A series of tests were done to study the influences and variation of strength of a single kind of expansive soil in the process of changing the soil state from nature and unsaturated and no cracks to saturated and no cracks to saturated and cracks fully developed by shear test and triaxial test. Test results show that water content and density and cracks influence the expansive soil strength; and water content and cracks influenc strength more than density does. It is concluded that cracks should be considered within the method of determining expansive soil strength. It is suggested that the strength of sample after 5 cycles of wet-dry should be used as the strength of cracks fully developed expansive soil. By residual strength tests, a conclusion is drawn that the residual strength of expansive soil was in proximity to the strength of cracks fully developed expansive soil; as a result, the residual strength could be used approximately as the strength of expensive soil in the region of cracks developed.