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以洞庭湖区沉积软土为对象进行循环振动三轴试验,研究不同动应力幅值、振动频率和围压下湖相软土的动力特性。结果表明:湖相软土轴向累积应变多呈稳定型增长,动应力幅值越大,累积应变越大,振动频率或围压越大,累积应变越小;动孔隙水压力随动应力幅值的增大而增大,受振动频率的影响较小,同时随围压的变化规律不统一,有待进一步研究;动应力幅值或振动频率越大,动弹性模量越小,围压越大,动弹性模量越大,且动弹性模量随振动次数的增加存在衰减现象,衰减规律亦受动应力幅值、振动频率和围压的影响。道路运营初期是软基沉降控制的关键阶段,为减小软基沉降,应特别重视对浅层软土的处理,并严格控制车载质量和车速。
A cyclic vibration triaxial test was conducted on the sedimentary soft soil in Dongting Lake area to study the dynamic characteristics of lacustrine soft soils under different dynamic stress amplitudes, vibration frequencies and confining pressure. The results show that the axial cumulative strain of the lacustrine soft clay is mostly stable, and the larger the dynamic stress amplitude is, the larger the cumulative strain is. The larger the vibration frequency or confining pressure is, the smaller the cumulative strain is. The dynamic pore water pressure with dynamic stress amplitude Value increases and increases, less affected by the frequency of vibration, while the law of variation with the confining pressure is not uniform, to be further studied; dynamic stress amplitude or vibration frequency, the smaller the dynamic modulus of elasticity, The larger the modulus of elasticity, the greater the modulus of elasticity, and the modulus of elasticity decreases with the increase of vibration frequency. The attenuation law is also affected by the stress amplitude, vibration frequency and confining pressure. The initial stage of road operation is the key stage of soft foundation settlement control. In order to reduce the settlement of soft foundation, special attention should be paid to the treatment of shallow soft soil, and the quality and speed of vehicles should be strictly controlled.