基于二元介质简化模型的滇池湖相沉积典型冻结泥炭质土力学特性研究  

Mechanical properties of typical frozen peat soil of lacustrine sediment in Dianchi Lake based on a simplified binary medium model

作　　者：屈俊童 王文彬 屈林河 QU Jun-tong;WANG Wen-bin;QU Lin-he(School of Architecture and Planning,Yunnan University,Kunming,Yunnan 650504,China;Yunnan Urban and Rural Planning Design and Research Institute,Kunming,Yunnan 650228,China)

机构地区：[1]云南大学建筑与规划学院,云南昆明650504 [2]云南省城乡规划设计研究院,云南昆明650228

出　　处：《岩土力学》2025年第1期233-243,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.52168038)。

摘　　要：为研究滇池湖相沉积典型冻结泥炭质土力学特性,利用改进的TSZ-2型全自动应变控制仪对滇池湖相沉积的泥炭质土进行不同影响因素下的低温三轴剪切试验,讨论不同温度、围压、含水率下冻结泥炭质土的力学特性,并引入二元介质模型理论对冻土的偏应力-应变关系进行分析。试验结果表明:随着应变的增加,偏应力-应变曲线可以划分为线弹性阶段、弹塑性阶段和基本稳定阶段,体积变形主要表现为体胀形态,冻土的变形特征均可用二元介质模型理论进行解释;在不同影响因素下,冻结泥炭质土峰值强度与围压、含水率呈正相关,与温度呈负相关;在试验条件内,围压对强度的影响先增后减,而含水率对强度表现出较高的敏感性,黏聚力随着温度的降低而增大,内摩擦角在20.56°~24.89°范围内波动。基于二元介质简化模型,构建适合冻结泥炭质土方程,并对结果进行验证,具有较好的适用性。To investigate the mechanical properties of frozen peat soil derived from Dianchi Lake's lacustrine deposits,a low-temperature triaxial shear test was conducted under various influencing factors,utilizing an improved TSZ-2 fully automatic strain control instrument.This study aimed to examine the mechanical behavior of frozen peat soil at different temperatures,confining pressures and moisture levels.Additionally,the binary medium model theory was introduced to analyze the deviatoric stress-strain relationship in frozen soil.The test results indicate that as strain increases,the deviatoric stress-strain curve divides into three stages:linear-elastic,elastic-plastic and stable stages.The volume deformation primarily involves bulk expansion,and the deformation characteristics of frozen peat soil can be explained using a binary medium model.The peak strength of frozen peat soil is positively correlated with confining pressure and moisture content,but negatively correlated with temperature.In the experimental setup,the impact of confining pressure on strength initially rises and then declines,while moisture content exhibits higher sensitivity to strength.Cohesion increases as temperature decreases,and the internal friction angle fluctuates between 20.56°and 24.89°.Based on the simplified binary medium model,the equations suitable for frozen peat soil are constructed and the results are verified with good applicability.

关 键 词：冻结泥炭质土 低温三轴试验 二元介质简化模型 

分 类 号：TU417[建筑科学—岩土工程]