辽西地区冻风积土动力特性试验分析

Dynamic test analysis of frozen aeolian soil under earthquake loading

动荷载作用下冻土的动力学参数是寒区工程抗震设计的关键。基于大量室内动三轴试验,研究了地震荷载作用下,辽西冻风积土的动强度σd、动变形εd、动弹性模量Ed和动阻尼比λd等动力学参数与土体含水量w、温度T、围压σ3c、动应力幅值σdamx和频率f等条件的关系。试验中采用三水平六因素的设计方法共进行了18组试验。试验结果表明,在相同振次水平条件下,冻土的动变形随动应力幅值的增大和温度上升而增大;在相同温度条件下,冻土的动剪切强度τd随着围压的增加而增加;低温冻土(-15℃)的动强度和动弹性模量要高于高温冻土(-2℃)的动强度和动弹性模量;冻土的动阻尼比随着变形和频率的增加而降低,随着含水量的增加而增加。上述规律为辽西风积土地区建设工程提供了较为可靠的抗震设计依据。

Dynamic parameters of frozen soil are the key of the aseismatic design in frost zone. Basing on a lot of in- situ dynamic triaxial tests, the paper research the relationship of dynamic stress, dynamic strain, dynamic modulus of elasticity and damping ratio to the moisture content, temperature, confining pressure, dynamic stress level and frequency of frozen aeolian soil in west of Liaoning Province under earthquake load. 18 group of tests were conducted by adopt three level six factors design method. The tests results show that with dynamic stress amplitude increase and temperature rise, the dynamic deformation will increasing in the same level of vibration numbers; Dynamic shear strength increasing with confining pressure increasing in the same temperature; The dynamic stress and dynamic modulus of elasticity of low-temperature frozen soil are superior than high-temperature frozen soil. The dynamic damping ratio decrease with deformation and frequency increasing, increasing with moisture content increasing. The results provide reliable aseismic design references to construction engineering in frozen aeolian soil area.