With climate change, permafrost under marshes in permafrost degradation areas thaws gradually, and the strength of permafrost decreases sharply, which seriously threatens the safety and stability of the structures on the surface. Based on the widening project of an old road in the permafrost degraded area of Northeast China, the changes of three fields of hydraulic, thermal, and mechanical at the research location are analyzed and predicted by establishing a simulation model. Taking the stress-temperature coupling damage model as the constitutive model, based on Biot porous medium theory and convective heat transfer equation. The thermohydromechanical coupling model of warm frozen soil is established to describe the thawing and consolidation process of warm permafrost with strength attenuation. The reliability of model calculation results and the scientificity of engineering treatment measures are analyzed and verified by field data collection. The results show that when the permafrost layer is not penetrated, the temperature field of surrounding soil will not be disturbed by normal temperature gravel pile group. However, the thawing process of permafrost is accelerated, the dissipation speed of excess pore water pressure caused by construction loading and thawing of permafrost is improved, the subgrade deformation caused by thawing and consolidation of permafrost is effectively reduced, and the stability of the subgrade during construction and road operation is ensured.

随着气候变化，多年冻土退化区沼泽下的冻土逐渐融化，冻土强度急剧下降，严重威胁地表结构的安全稳定。以东北多年冻土退化区老路拓宽工程为例，通过建立仿真模型，对研究区水力、热力和力学三个领域的变化进行分析和预测。以应力-温度耦合损伤模型为本构模型，基于Biot多孔介质理论和对流传热方程。建立暖冻土的热流体力学耦合模型，描述暖冻土的解冻固结过程，强度衰减。通过现场数据采集分析验证模型计算结果的可靠性和工程处理措施的科学性。结果表明，在未穿透多年冻土层时，常温碎石桩群不会干扰周围土壤的温度场。但冻土融化进程加快，施工荷载和冻土融化引起的超孔隙水压力消散速度加快，冻土融化固结引起的路基变形有效减少，路基在施工过程中的稳定性得到改善。建设和道路运营得到保障。常温碎石桩群不会干扰周围土壤的温度场。但冻土融化进程加快，施工荷载和冻土融化引起的超孔隙水压力消散速度加快，冻土融化固结引起的路基变形有效减少，路基在施工过程中的稳定性得到改善。建设和道路运营得到保障。常温碎石桩群不会干扰周围土壤的温度场。但冻土融化进程加快，施工荷载和冻土融化引起的超孔隙水压力消散速度加快，冻土融化固结引起的路基变形有效减少，路基在施工过程中的稳定性得到改善。建设和道路运营得到保障。