基于亚塑性理论的低液限粘土本构模型与改善试验研究

发布时间：2018-01-11 07:18

本文关键词：基于亚塑性理论的低液限粘土本构模型与改善试验研究　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着经济的飞速发展,城市的扩张需要修建越来越多的高速公路。高速公路不可避免的会穿越许多地质条件不明的区域。此类区域内尚未存在有关于土体工程性质等的研究。土体的工程性质一直是本领域内较难以研究的问题之一,如果只是经过简单的类比推理而没有深入研究土体工程性质,则会在其应用的过程中产生一系列的问题。本文依托潍北平原高速公路修建过程中遇到的特殊土质及其在应用过程中出现的一系列问题,开展了详细而深入的研究。具体研究工作如下:(1)依托实体工程项目,实地调查了路线穿越场区自然地理环境和水文、工程地质条件。根据该工程项目路基填料指定取土场的区域地质条件,确定了现场土体的取样方案。(2)针对从取土场获取的土样,开展了较全面的室内试验,首次深入全面地研究了该地区土体试样的工程性质并按照规范标准确定了其名称为低液限粘土。在路基填筑施工期开展了现场试验,埋设了电子监测设备,研究了低液限粘土用作路基填料时的力学特性和变形规律。(3)研究了亚塑性理论的起源,重点分析了其限制条件。以Gudehus-Bauer亚塑性本构模型为主线,首次引入受含水率影响的粘聚力变量并依据室内土工试验和现场试验的试验成果,研究了适用于压实状态下低液限粘土的亚塑性本构模型。(4)参照现场使用的路床区改善低液限粘土方案,并结合室内试验得出的低液限粘土工程性质,分析了不同外加材料对低液限粘土的改善机理,制定了改善低液限粘土对比试验方案并进行了室内力学性能试验,对比分析了不同方案的改良效果,提出了满足规范要求的新型低液限粘土改良方案。(5)整理室内改良试验得到的成果,在现场选取路基试验段进行加固土的路用力学性能试验,包括路面弯沉试验及堆载试验。选用原方案的路基试验段并按照新型改良方案铺设路床区改善土层,按照规范标准进行了弯沉试验,试验结果表明改善土层的短时强度能满足要求。选取现场原位试验中埋设电子监测设备的路基区间为试验段,一部分铺设改善土层而另一部分不进行处理以进行对比试验,首次开展了现场路基堆载观测试验以研究路床区改善土层的长期稳定强度。首次结合前期高速公路路堤承载特性的模型试验的研究成果,对室内试验得出的改善土现场试验方案进行了整体评价。本文对于该区域土体工程性质的研究,填补了该区域关于低液限粘土工程性质资料的空白,能够为将来研究该区域地质条件的研究人员提供一定的参考和借鉴,具有一定的理论意义;本文对于低液限粘土开展的改善试验研究,研究成果能为将来在该区域需要进行低液限粘土改善处理的工程项目指明了方向,具有一定的经济价值和社会价值。
[Abstract]:With the rapid development of economy. The expansion of cities requires the construction of more and more highways. Expressways inevitably cross many areas with unknown geological conditions. There has not been any research on the engineering properties of soil in such areas. The nature of the process has always been one of the more difficult problems in this field. If only through simple analogy reasoning without in-depth study of soil engineering properties. In the process of its application a series of problems will arise. This paper relies on the Weibei Plain Expressway construction process encountered in the special soil quality and in the application of a series of problems. A detailed and in-depth study has been carried out. The specific research work is as follows: 1) relying on the physical engineering project, the physical geographical environment and hydrology of the route crossing the field area have been investigated on the spot. Engineering geological conditions. According to the regional geological conditions of the subgrade filling site designated by the project, the sampling plan of the field soil mass is determined, which is aimed at the soil samples obtained from the collection site. A more comprehensive indoor test was carried out, and the engineering properties of the soil samples in this area were studied thoroughly for the first time. According to the standard of the code, the name of the soil sample was determined as low liquid limit clay, and the field test was carried out during the construction period of the subgrade. The mechanical properties and deformation law of low liquid limit clay used as subgrade filler were studied. (3) the origin of subplastic theory was studied. The limitation conditions are analyzed. The main line is the Gudehus-Bauer hypoplastic constitutive model. The cohesion variable affected by moisture content was introduced for the first time, and the results of indoor geotechnical test and field test were used for the first time. The hypoplastic constitutive model for low liquid limit clay under compaction is studied. According to the road bed area used in the field, the scheme of improving low liquid limit clay is studied, and the engineering properties of low liquid limit clay obtained by laboratory test are also studied. The improvement mechanism of low liquid limit clay with different applied materials was analyzed, the contrast test scheme of improving low liquid limit clay was established, and the indoor mechanical property test was carried out, and the improvement effect of different schemes was compared and analyzed. The paper puts forward a new low liquid limit clay improvement scheme, which meets the requirements of the code, and arranges the results obtained from the indoor improvement test, and selects the roadbed test section on the spot to carry out the road mechanics performance test of the strengthened soil. Including pavement deflection test and surcharge test. The original roadbed test section was selected and the soil layer was improved according to the new improved road bed area. The deflection test was carried out according to the standard of the code. The test results show that the short-term strength of soil layer can meet the requirements. The section of roadbed embedded with electronic monitoring equipment in in-situ test is selected as the test section. One part was laid to improve the soil layer, while the other part was not treated for comparative testing. It is the first time to study the long-term stability strength of soil layer in roadbed area by field observation test of embankment load, and combine the research results of model test of embankment bearing characteristics in the early stage of expressway for the first time. In this paper, the research on the engineering properties of soil in this area fills up the blank of the engineering properties of low liquid limit clay in this area. It can provide a certain reference and reference for the researchers who study the geological conditions of the region in the future, which has certain theoretical significance. In this paper, the experimental research on the improvement of low liquid limit clay has been carried out. The results of the research can point out the direction of the engineering projects which need to improve the low liquid limit clay in this area in the future, and have certain economic and social value.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416

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