西峰及洛川黃土剖面地層擊實特性研究
本文關(guān)鍵詞: 黃土 黃土地層 擊實試驗 最佳含水率 最大干密度 出處:《長安大學(xué)》2014年碩士論文 論文類型:學(xué)位論文
【摘要】:黃土在我國分布廣泛,黃土路基的沉陷變形是黃土地區(qū)公路的主要病害之一。解決路基沉陷變形的核心是提高路基土的壓實密度,,因此,黃土路基能否達(dá)到標(biāo)準(zhǔn)的壓實度就顯得尤為重要。影響黃土壓實的因素很多,但是對黃土壓實起控制性影響的因素主要來講有內(nèi)部因素(黃土粒度成分、顯微結(jié)構(gòu))和外部因素(含水率、壓實功)等。 本文以位于隴東(六盤山以東)的慶陽市孔家塬和位于渭北黃土高原溝壑區(qū)的洛川縣石家莊黃土地層剖面為研究對象,通過二十余人耗時九個月的實地考察、現(xiàn)場取樣、室內(nèi)土工試驗、標(biāo)準(zhǔn)重型擊實試驗、理論分析等,對這兩個黃土剖面的地層概況、最佳含水率和最大干密度進(jìn)行了研究,對比總結(jié)了兩個具有代表性的不同區(qū)域黃土沿地層垂直方向的擊實特性,并分析得出以下結(jié)論: 1.在不同黃土分布區(qū),由西向東,各地層最佳含水率范圍并無明顯變化規(guī)律,最大干密度范圍逐漸增大。 2.在不同黃土分布區(qū)域,由西向東,黃土剖面黃土層加權(quán)最佳含水率基本接近,加權(quán)最大干密度逐漸減。还磐寥缹蛹訖(quán)最佳含水率和加權(quán)最大干密度都逐漸增大。 3.坡頭黃土的最大干密度和最佳含水率較其它黃土大,馬蘭黃土、離石黃土、午城黃土的最大干密度和最佳含水率都比較接近。 4.比較兩個不同黃土剖面在不同地質(zhì)年代Q4、Q3、Q2、Q1的土樣擊實試驗所得加權(quán)最佳含水率及加權(quán)最大干密度。由于孔家塬剖面全新世Q4層和早更新世Q1層的缺失,無法比較;在相同地質(zhì)年代Q3層或Q2層,由西向東,不同地區(qū)黃土的加權(quán)最佳含水率逐漸增大,加權(quán)最大干密度逐漸減小。 5.同一黃土地區(qū),黃土剖面的黃土層與古土壤層的加權(quán)最大干密度和加權(quán)最大含水率都基本接近。 6.就不同黃土地區(qū)的加權(quán)最佳含水率和加權(quán)最大干密度來比較,由西向東,加權(quán)最佳含水率逐漸減小,加權(quán)最大干密度逐漸增大。
[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.
【學(xué)位授予單位】:長安大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2014
【分類號】:U416.1
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