中文摘要：

在软土地基上修建低路堤时,软土地基经常会出现失稳、变形过大等问题,从而造成路面开裂,在此情况下通常会通过修建人工硬壳层对软基进行处治。目前,对于软土地基人工硬壳层相应的设计参数和处治方法并未进行深入的研究,且大部分处理方法都是通过工程实践和室内试验总结得到的。为优化用于处治软土路基的人工硬壳层设计方案,并提出软土地基上人工硬壳层设计参数的推荐取值范围,首先利用有限元软件ABAQUS在基于大、小变形理论基础上建立软土地基上路基路面有限元模型,对比分析软土地基模型对计算结果的影响程度,选定能够合理模拟软土地基的有限元模型;然后分析人工硬壳层的模量、厚度、宽度等参数对软土地基和路面力学响应的影响;最后推荐软土地基上人工硬壳层设计参数的合理取值范围。研究结果表明：含人工硬壳层软基上修建低路堤后,主要有软基整体承载力不足导致的剪切破坏、软基沉降变形过大和路基当量模量过低引起的路面提前开裂3种破坏形式;与扩展的Drucker-Prager模型相比,基于大变形理论的多孔介质弹性模型在模拟软土地基时表面沉降增大45.1%,附加应力降低4.9%,采用大变形理论模拟软土地基更合理;硬壳层的模量、厚度和宽度在一定范围内变化时,随着其数值的增加,软土地基的应力和位移逐渐降低,路面承受的附加应力逐渐增大;推荐软土地基上人工硬壳层的设计模量为150-300 MPa,处治深度为1-2m,每侧宽度比路基边坡增加1m。

英文摘要：

The instability and large deformation of soft foundation occur frequently with pavement cracking when low embankment is constructed on soft foundation, and artificial hard crust is usually used to solve this problem. At present, corresponding design parameters and treatment methods of artificial hard crust on soft foundation have not been deeply studied, and most of the methods come from engineering experience and laboratory experiment. To optimize the design of artificial hard crush for the treatment of soft foundation and put forward corresponding value range of design parameters for artificial hard crust, finite element model of road on softfoundation was established by using finite element software ABAQUS based on large and small deformation theories. Influence degree of two soft foundation models on the results were compared, and finite element model which could reasonably simulate soft foundation was chosen. Then effects of modulus, thickness, width of artificial hard crust on mechanical response and soft foundation were analyzed. Finally, value range of design parameters for artificial hard crust on soft foundation were recommended. The results show that when the low embankment is constructed on soft foundation containing artificial hard crust, the shear failure caused by low bearing capacity, large settlement deformation of soft foundation and pavement early cracking caused by low equivalent subgrade modulus. Compared with expanded Drucker-Prager model, when porous medium elasticity model based on large deformation theory is used to simulate soft foundation, the surface settlement of pavement increases by 45.1%, while the additional stress decreases by 4.9%, which proves that large deformation theory is more reasonable compared to small deformation theory for simulating soft foundation. Moreover, as modulus, thickness and width of artificial hard crust increase within a proper range, stress and displacement of soft foundation decrease while additional stress of pavement increases. The ranges of modulus an