湿度波动下黏质土路基回弹模量演化规律

Study of the influence of moisture content change cyclicity on modulus evoluation law of cohesive subgrade soil

摘要:

历经多次干湿循环的路基土，其力学性能劣化现象非常突出，路基的路用性能也随之衰减。基于室内试验研究含水率周期性变化对路基回弹模量（MR）的影响规律。遵循现场测试含水率变化态势，利用“透水石渗水—静置—烘箱脱水—透水石渗水—静置—烘箱脱水……”一系列湿度循环来模拟现场路基土的含水率波动过程，同时测试其回弹模量。结果表明黏质路基土回弹模量受含水率变化的影响非常明显，回弹模量随湿度循环次数的增大而减小；在相同的应力状态下，黏质路基土的平衡含水率EMC越高，其回弹模量值对含水率的周期性变化越敏感，且MR值趋于不稳定状态。

Abstract:

After Experience of dry-wet cycle，Its mechanical properties will be irreversible changes. The mechanical properties influenced on moisture content changes cyclicity of cohesive subgrade soil was studied by indoor test. And the extent of the resilience modulus attenuation of subgrade result in frequently dry-wet cycle was analyzed. Use the method of a series of humidity cycle as “water seepage under the permeable stone –standing-oven dehydration……” to imitate the scene of the subgrade soil moisture content fluctuation process. The resilience of subgrade soil was tested by the system of UTM. The results show that, moisture content changes cyclicity have influence in resilience modulus of cohesive subgrade soil. The resilience modulus decrease following the increase of cycle times. In the same stress state, The higher the equilibrium moisture content, The more sensitive the resilience modulus changes.