原状黄土和水泥土损伤比强度理论及地表黄土塑性流动深度预测  

Damage ratio strength theory of undisturbed loess and cemented soil and prediction of plastic flow depth of surface loess

作　　者：吴霞 丁发兴[1] 王宁 WU Xia;DING Faxing;WANG Ning(School of Civil Engineering,Central South University,Changsha 410075,China;School of Civil Engineering,Central South University of Forestry and Technology,Changsha 410004,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南林业科技大学土木工程学院,湖南长沙410004

出　　处：《铁道科学与工程学报》2025年第2期863-874,共12页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51978664);中南大学中央高校基本科研业务费专项资金资助项目(2022ZZTS0603);中南大学高性能计算平台资助项目。

摘　　要：损伤比强度理论已应用于混凝土和各向同性岩石等黏聚摩擦材料,得到了很好的预测结论。黄土在自然界分布广泛,水泥土是一种人工处理土,主要包括水泥加固土和水泥稳定土两大类,黄土和水泥土均属于黏聚摩擦材料。将损伤比强度理论推广应用于原状黄土和水泥土的三轴强度预测。首先,基于原状黄土和水泥土的三轴受压强度包络面特征和现有试验数据建立原状黄土和水泥土损伤比强度理论,并推荐了损伤比表达式中的5个经验系数取值,该理论预测结果与不同类型原状黄土和水泥土的三轴强度试验结果吻合良好。然后,通过损伤比强度理论与Mohr-Coulomb单剪强度准则、双剪强度准则、Lade强度准则和广义SMP强度准则进行比较,表明提出的强度理论有较高的计算精度。此外,损伤比强度理论对应子午线压端与平均主应力轴相交,而其余准则对应的各子午线压端开口。最后,根据五经验系数下的损伤比强度理论,可预测黄土和水泥土具有弹脆性、弹塑性和塑性流动3种状态,反映了该类土体单轴受压压碎以及三轴受压塑性流动的指标量化,且高平均主压应力下土体将由弹塑性向塑性流动转变的特征,为基础持力层破坏而产生的不均匀沉降现象提供理论依据。根据原状黄土损伤比强度理论预测重力作用下地表深处黄土存在塑性流动深度,预测结果分别为75 m和367 m。The damage ratio strength theory has been applied to various types of cohesive-frictional materials,including concrete and isotropic rocks,providing reliable predictive results.Loess,which exists widely in nature,and cemented soil,a type of artificially treated soil consisting of cement treated soil and cement stabilized soil,both belong to cohesive-frictional materials.In this paper,the damage ratio strength theory was applied to predict the triaxial strength of undisturbed loess and cemented soil.First,based on the characteristics of the triaxial compression strength envelope and existing experimental data of undisturbed loess and cemented soil,a damage ratio strength theory for undisturbed loess and cemented soil was established.Five empirical coefficients for the damage ratio expression were recommended,and the predicted results of this theory were in good agreement with the triaxial strength data of different types of undisturbed loess and cemented soil.Then,a comparative analysis with Mohr-Coulomb single-shear criterion,twin-shear criterion,Lade criterion,and generalized SMP strength criterion demonstrated the higher computational accuracy of the proposed strength theory.Moreover,it was indicated that the damage ratio strength theory reflects the intersection of meridians with the hydrostatic pressure axis,whereas other criteria correspond opening meridians.Finally,based on the damage ratio strength theory with five empirical coefficients,it is possible to predict that loess and cemented soil exhibit three states:elastic-brittle,elastic-plastic,and plastic flow.This theory quantifies the indicators of uniaxial compressive crushing and triaxial compressive plastic flow for such soil types,and reveals the transition from elastoplasticity to plastic flow under high mean principal stress for soil materials,which provide a theoretical basis for the uneven settlement caused by the failure of foundation bearing stratum.The plastic flow depth of loess in deep surface due to gravity can be predicted according to the

关 键 词：原状黄土 水泥土 强度理论 损伤比 塑性流动 

分 类 号：TU43[建筑科学—岩土工程]