高液限黏土的动力响应研究

Research on Dynamic Response of High Liquid Limit Clay

高液限黏土是一种特殊土体,为探究其在行车荷载作用下的动力响应,本文采用GDS动三轴试验模拟车辆荷载作用下高液限黏土路基性能随车辆载重(动应力幅值)、循环周次、压实度、含水量以及围压(路基埋深)等条件的响应规律。结果表明:1) 不同动应力幅值作用下,高液限黏土存在3种响应模式,临界动应力介于20~30 kPa之间,试样动弹性模量随循环周次增加而逐渐减小,并在N = 500时趋于稳定;2) 含水率对高液限黏土路基的动力特性影响于最为显著明显,压实度次之,建议将路基填筑含水率低于最优含水率2%;3) 相同动应力幅值条件下,固结围压越大,高液限黏土累积应变均越小,路基埋深越深,动荷载对高液限黏土的影响越小。研究结果对高液限黏土路基设计具有重要参考价值。

High liquid limit clay is a special kind of soil. In order to investigate its dynamic response under driving load, GDS dynamic triaxial test was carried out to simulate the response of high-liquid-limit clay subgrade performance under vehicle loading with vehicle load (dynamic stress amplitude), cycle times, compaction, water content and confining pressure (subgrade burial depth). The results show that: 1) Under the action of different dynamic stress amplitudes, there are three response modes for high liquid limit clays. The critical dynamic stress is between 20 kPa and 30 kPa. The dynamic elastic modulus of the sample gradually decreases with the increase of cycle cycles, and It tends to be stable when N = 500;2) The moisture content has the most significant impact on the dynamic characteristics of the high liquid limit clay roadbed, followed by the degree of compaction. It is recommended that the water content of the roadbed filling be lower than the optimal water content of 2%;3) Under the same dynamic stress amplitude conditions, the greater the consolidation confining pressure, the smaller the cumulative strain of the high-liquid-limit clay, the deeper the subgrade is buried, and the smaller the impact of dynamic load on the high-liquid-limit clay. The research results have important reference value for the design of high liquid limit clay roadbed.