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结合湖北省宜昌市小溪塔至鸦鹊岭一级公路改建工程,风化砂改良膨胀土路基施工项目,对掺入不同比例风化砂的膨胀土进行了直剪试验、无侧限抗压强度试验、CBR试验和回弹模量试验,探讨不同掺砂比例对强度指标的影响及其变化规律。试验研究结果表明,掺砂能改善膨胀土的力学强度性能,掺砂之后的膨胀土的强度指标可以达到路基材料的要求;掺砂对内摩擦角的影响较小,对CBR值的影响较大,黏聚力、无侧限抗压强度和回弹模量随着掺砂比例的改变而改变;随着掺砂比例增大,内摩擦角增大,CBR值增大,黏聚力、无侧限抗压强度和回弹模量先增大后减小;随着掺砂量的增加,内摩擦角增大的趋势先快后慢,CBR值和黏聚力的变化趋势出现波动,无侧限抗压强度和回弹模量的变化趋势由快逐渐趋于平稳。
Combining with the reconstruction project of Xiaoxi Tower to Yaqueling Grade I Highway in Yichang, Hubei Province, weathered sand improved the construction project of expansive soil subgrade, conducted the direct shear test and the unconfined compressive strength test of expansive soil with different proportion of weathered sand. , CBR test and the rebound modulus test to explore the impact of different proportion of sand on the strength index and its variation. The experimental results show that the mechanical properties of the expansive soils can be improved by using sand. The strength index of the expansive soils after the sand compaction can meet the requirements of roadbed materials. The influence of sand content on the internal friction angle is small and the CBR value is greatly affected , Cohesion, unconfined compressive strength and modulus of elasticity change with the change of sand mixing ratio. With the increase of sand mixing ratio, the internal friction angle increases, CBR value increases, cohesion, no The compressive strength and the rebound modulus first increase and then decrease; with the increase of sand content, the trend of increasing the internal friction angle first and then slow, the trend of CBR value and cohesion fluctuates, without The trend of confining compressive strength and resilience modulus tends to be steady from fast.