西峰及洛川黄土剖面地层击实特性研究

发布时间：2018-01-20 13:53

本文关键词： 黄土黄土地层击实试验最佳含水率最大干密度　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：黄土在我国分布广泛，黄土路基的沉陷变形是黄土地区公路的主要病害之一。解决路基沉陷变形的核心是提高路基土的压实密度，，因此，黄土路基能否达到标准的压实度就显得尤为重要。影响黄土压实的因素很多，但是对黄土压实起控制性影响的因素主要来讲有内部因素(黄土粒度成分、显微结构)和外部因素(含水率、压实功)等。本文以位于陇东(六盘山以东)的庆阳市孔家塬和位于渭北黄土高原沟壑区的洛川县石家庄黄土地层剖面为研究对象，通过二十余人耗时九个月的实地考察、现场取样、室内土工试验、标准重型击实试验、理论分析等，对这两个黄土剖面的地层概况、最佳含水率和最大干密度进行了研究，对比总结了两个具有代表性的不同区域黄土沿地层垂直方向的击实特性，并分析得出以下结论： 1．在不同黄土分布区，由西向东，各地层最佳含水率范围并无明显变化规律，最大干密度范围逐渐增大。 2．在不同黄土分布区域，由西向东，黄土剖面黄土层加权最佳含水率基本接近，加权最大干密度逐渐减小；古土壤层加权最佳含水率和加权最大干密度都逐渐增大。 3．坡头黄土的最大干密度和最佳含水率较其它黄土大，马兰黄土、离石黄土、午城黄土的最大干密度和最佳含水率都比较接近。 4．比较两个不同黄土剖面在不同地质年代Q4、Q3、Q2、Q1的土样击实试验所得加权最佳含水率及加权最大干密度。由于孔家塬剖面全新世Q4层和早更新世Q1层的缺失，无法比较；在相同地质年代Q3层或Q2层，由西向东，不同地区黄土的加权最佳含水率逐渐增大，加权最大干密度逐渐减小。 5．同一黄土地区，黄土剖面的黄土层与古土壤层的加权最大干密度和加权最大含水率都基本接近。 6．就不同黄土地区的加权最佳含水率和加权最大干密度来比较，由西向东，加权最佳含水率逐渐减小，加权最大干密度逐渐增大。
[Abstract]:Loess is widely distributed in China, the settlement deformation of loess roadbed is one of the main diseases of highway in loess area. The core of settlement deformation is to improve the compaction density of subgrade soil. Whether the loess subgrade can reach the standard compaction degree is particularly important. There are many factors that influence the loess compaction, but the main factors affecting loess compaction are internal factors (loess granularity composition). Microstructure) and external factors (moisture content, compaction work), etc. In this paper, the loess profile of Shijiazhuang in Luochuan County, located in the gully region of Weibei Loess Plateau and Qingyang City, located in the east of Longdong (east of Liupanshan), is taken as the research object. It takes more than 20 people nine months of field investigation. Field sampling, laboratory geotechnical test, standard heavy compaction test, theoretical analysis and so on, this paper studies the stratigraphic profile, optimum moisture content and maximum dry density of the two loess sections. The compaction characteristics of loess along the vertical direction of strata in two representative regions are compared and summarized, and the following conclusions are obtained: 1. In different loess distribution areas, from west to east, the optimum moisture content range of each layer has no obvious change rule, and the maximum dry density range increases gradually. 2. In different loess distribution areas, from west to east, the weighted optimum moisture content of loess profile is close to that of loess profile, and the weighted maximum dry density decreases gradually; The weighted optimum moisture content and the weighted maximum dry density of paleosol gradually increased. 3. The maximum dry density and the optimum moisture content of the loess in Potou are larger than those of the other loess. The maximum dry density and the optimum moisture content of the Ma Lan loess, the Lishi loess and the Wucheng loess are close to each other. 4. Comparison of two different loess sections at different geological ages Q4Q3Q2. The weighted optimum moisture content and the weighted maximum dry density were obtained from the soil sample compaction test of Q1. Due to the absence of the Holocene Q4 layer and the early Pleistocene Q1 layer of the Kongjiayuan section, there is no comparison. At the same geological age, from west to east, the weighted optimum moisture content of loess increases and the weighted maximum dry density decreases from west to east in the Q3 or Q2 layers of the same geological age. 5. In the same loess area, the weighted maximum dry density and the weighted maximum moisture content of loess profile and paleosol layer are close to each other. 6. The weighted optimum moisture content and the weighted maximum dry density in different loess regions are compared. From west to east, the weighted optimum moisture content decreases gradually, and the weighted maximum dry density increases gradually.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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