人工硬壳层上低路堤大变形理论分析
发布时间：2019-07-05 15:34
【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。
[Abstract]:When the low embankment is built on the soft soil foundation, the soft soil foundation often has the problems of instability and excessive deformation, which leads to the pavement cracking. In this case, the soft foundation will usually be treated by the construction of artificial hard shell. At present, the corresponding design parameters and treatment methods of artificial hard shell on soft soil foundation have not been deeply studied, and most of the treatment methods are summarized through engineering practice and laboratory tests. In order to optimize the design scheme of artificial hard shell used to treat soft soil subgrade, and put forward the recommended value range of artificial hard shell design parameters on soft soil foundation, firstly, the finite element model of subgrade pavement on soft soil foundation is established on the basis of large and small deformation theory by using finite element software ABAQUS, the influence degree of soft soil foundation model on the calculation results is compared and analyzed, and the finite element model which can reasonably simulate soft soil foundation is selected. Then the effects of modulus, thickness and width of artificial hard shell on the mechanical response of soft soil foundation and pavement are analyzed. Finally, the reasonable range of design parameters of artificial hard shell on soft soil foundation is recommended. The results show that after the construction of low embankment on soft foundation with artificial hard shell, there are three kinds of failure forms: shear failure caused by insufficient overall bearing capacity of soft foundation, excessive settlement deformation of soft foundation and early cracking caused by low equivalent modulus of subgrade. Compared with the extended Drucker-Prager model, the elastic model of porous media based on large deformation theory increases the surface settlement by 45.1% and reduces the additional stress by 4.9% when simulating soft soil foundation, so it is more reasonable to use large deformation theory to simulate soft soil foundation. When the modulus, thickness and width of the hard shell change in a certain range, with the increase of its numerical value, the stress and displacement of the soft soil foundation decrease gradually, and the additional stress on the pavement increases gradually. It is recommended that the design modulus of the artificial hard shell on the soft soil foundation is 150 鈮，
本文编号：2510627
[Abstract]:When the low embankment is built on the soft soil foundation, the soft soil foundation often has the problems of instability and excessive deformation, which leads to the pavement cracking. In this case, the soft foundation will usually be treated by the construction of artificial hard shell. At present, the corresponding design parameters and treatment methods of artificial hard shell on soft soil foundation have not been deeply studied, and most of the treatment methods are summarized through engineering practice and laboratory tests. In order to optimize the design scheme of artificial hard shell used to treat soft soil subgrade, and put forward the recommended value range of artificial hard shell design parameters on soft soil foundation, firstly, the finite element model of subgrade pavement on soft soil foundation is established on the basis of large and small deformation theory by using finite element software ABAQUS, the influence degree of soft soil foundation model on the calculation results is compared and analyzed, and the finite element model which can reasonably simulate soft soil foundation is selected. Then the effects of modulus, thickness and width of artificial hard shell on the mechanical response of soft soil foundation and pavement are analyzed. Finally, the reasonable range of design parameters of artificial hard shell on soft soil foundation is recommended. The results show that after the construction of low embankment on soft foundation with artificial hard shell, there are three kinds of failure forms: shear failure caused by insufficient overall bearing capacity of soft foundation, excessive settlement deformation of soft foundation and early cracking caused by low equivalent modulus of subgrade. Compared with the extended Drucker-Prager model, the elastic model of porous media based on large deformation theory increases the surface settlement by 45.1% and reduces the additional stress by 4.9% when simulating soft soil foundation, so it is more reasonable to use large deformation theory to simulate soft soil foundation. When the modulus, thickness and width of the hard shell change in a certain range, with the increase of its numerical value, the stress and displacement of the soft soil foundation decrease gradually, and the additional stress on the pavement increases gradually. It is recommended that the design modulus of the artificial hard shell on the soft soil foundation is 150 鈮，
本文编号：2510627
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