考虑温度效应的路基粗粒填料亚塑性模型

为了研究温度效应对路基粗粒填料静力剪切特性的影响，对GDS大三轴试验系统进行温控模块升级，采用循环流体加热模式实现对试样温度的精准控制. 选取浙江省某路基采石场碎石填料进行饱和排水剪切试验，分析不同温度下低围压路基填料静力剪切特性. 基于试验数据，建立剪胀指数与围压之间的关系，对von Wolffersdorff亚塑性模型进行改进以反映路基填料在低围压下的剪胀性. 在此基础上，提出温度对粗粒填料剪胀性及强度影响的本构关系式，建立考虑温度效应的路基填料亚塑性模型. 研究表明，温度升高使密实路基填料表现出软化现象，峰值强度随温度升高而降低；路基填料围压越高，峰值强度随温度的衰减越明显；残余强度基本不受温度变化影响. 所建立的模型能够模拟低围压填料强度与围压的非线性关系，准确反映不同温度下密实路基填料的剪切特性，可以作为温度效应下粗粒土剪切特性模拟的有效工具.

Hypoplastic model for road base coarse-grained materials accounting for temperature effect

The GDS large-scale triaxial test system was upgraded by the temperature control module and the circulating fluid heating mode was used to achieve precise control and monitoring of the sample temperature, in order to study the temperature effect on the static shear characteristics of road base coarse-grained filling materials. The crushed stone filler of a roadbed quarry in Zhejiang Province was selected for saturated drainage shear test, and the static characteristics of road base filling materials under different low confining pressures and temperatures were analyzed. The relationship between the dilatancy parameter and the confining pressure was established based on experimental data. The von Wolffersdorff hypoplastic model was improved to reflect the dilatancy of the road base filling materials under low confining pressure. Constitutive relation for the influence of temperature on dilatancy and strength was proposed based on the improved model, and a hypoplastic model for road base coarse-grained materials accounting for temperature effect was established. Research show that increasing temperature makes road base filling materials soft, the peak strength of the road base filling materials will decrease with the increase of temperature, and the higher the confining pressure, the more obvious the peak strength attenuation with temperature. However, the temperature change will basically not affect the residual strength of the roadbed filler. The established model can simulate the nonlinear relationship between strength and confining pressure of road base coarse-grained materials, accurately reflect the shear characteristics under different temperatures, and can be used as an effective tool for simulating the shear characteristics of coarse-grained soil under temperature effects.