發(fā)布時間：2018-06-04 17:01

  本文選題：馬蘭黃土 + 直剪試驗��； 參考：《太原理工大學》2017年碩士論文

【摘要】：黃土是一種特殊的結(jié)構(gòu)性土,受生成環(huán)境以及應(yīng)力歷史環(huán)境的影響,存在明顯的孔隙型結(jié)構(gòu)和豎向節(jié)理。黃土沉積過程中形成的水平成層性特征以及孔隙和豎向節(jié)理的存在,使黃土的力學性質(zhì)存在明顯的差異。不同區(qū)域內(nèi)的黃土,不同影響因素對其力學性質(zhì)的影響也不盡相同。地球上黃土和黃土狀土的面積約為1300萬km2,占到全球大陸總面積的9%以上,分布十分廣泛。尤其是在中國的中西部以及北部地區(qū)有廣泛的黃土覆蓋區(qū)。隨著國家“西部大開發(fā)”戰(zhàn)略以及“一帶一路”戰(zhàn)略的實施,黃土地區(qū)工程數(shù)量日趨增加且規(guī)模逐步擴大。同時在公路、鐵路、橋梁、隧道等多種交通基礎(chǔ)設(shè)施的建設(shè)中,也都面臨著各種黃土問題。因此,對于黃土力學特性的研究變得日臻重要。本文基于前人關(guān)于黃土抗剪強度以及各向異性方面的研究,通過人工開挖探井,取原狀馬蘭黃土試樣,密封后用被子包好,運回實驗室。通過干密度、孔隙比、顆粒重度、液塑限、粒徑分析等物理實驗和室內(nèi)直剪試驗,尋找其間差距并究其原因。直剪試驗所用試樣,為烘干的含水率為0的原狀馬蘭黃土,用線切割機將烘干的黃土切割成圓柱狀,然后用細砂紙打磨成標準樣。分別對取自7個探井的試樣,從豎直向(剪切面平行于水平向)、東西向(剪切面平行于坡向)和南北向(剪切面平行于走向)三個方向做直剪試驗,每個方向剪3個試樣,共63組直剪試樣,分別測其抗剪強度和剪切過程中的豎向位移量。結(jié)果表明:該區(qū)域內(nèi)的馬蘭黃土,存在明顯的各向異性;該區(qū)域內(nèi)的原狀馬蘭黃土在含水率為0時,從不同方向剪切試樣,試樣在剪切過程中的豎向位移量無明顯規(guī)律;該區(qū)域內(nèi)的原狀馬蘭黃土,豎直向的密實度和抗剪強度明顯大于水平向,豎直向的抗剪強度約為水平向的1.15倍;東西和南北向的抗剪強度差異不大,較為接近,南北向略大于東西向�？沙醪秸J為:該區(qū)域內(nèi)的馬蘭黃土,豎向節(jié)理和孔隙性結(jié)構(gòu)特征,對其力學性質(zhì)的影響更為明顯。
[Abstract]:Loess is a special structural soil, which is influenced by the generated environment and the historical environment of stress. There are obvious pore structure and vertical joint. The horizontal stratification characteristics and the existence of pore and vertical joints in the process of loess deposition make the mechanical properties of the Loess distinct difference. The Loess in different regions is different. The influence factors have different effects on the mechanical properties of the earth. The earth's loess and loessial soil area is about 13 million km2, accounting for more than 9% of the total area of the global continent and widely distributed, especially in the central and western regions of China and in the northern region. With the implementation of the "road" strategy, the number of projects in the loess region is increasing and the scale is gradually expanding. At the same time, all kinds of loess problems are faced in the construction of road, railway, bridge, tunnel and other transportation infrastructure. Therefore, it is becoming more and more important to study the mechanical properties of loess. And the study of anisotropy, through the artificial excavation of the well, take the original Ma Lan loess sample, sealed with the quilt wrapped, transported back to the laboratory. Through the dry density, the pore ratio, the grain weight, the liquid plastic limit, the particle size analysis and other physical experiments and the indoor direct shear test, looking for the gap between them and the reasons. The original Ma Lan loess, which has a water rate of 0, cuts the dried loess into a cylindrical shape with a wire cutting machine and then grinded into a standard sample with fine sand paper. The specimens from 7 exploratory wells, respectively, are vertical shear tests from the vertical direction (the shear plane parallel to the horizontal direction), the east-west direction (the shear plane parallel to the slope) and the south north direction (parallel to the direction of the shear plane), respectively. The shear strength and the vertical displacement in the shear process were measured in 63 groups of 3 samples in each direction. The results showed that the Ma Lan loess in the region had obvious anisotropy, and the vertical displacement of the original Ma Lan loess in the region was in the shear process when the water content was 0. The original Ma Lan loess in this area has a vertical direction of compactness and shear strength that is obviously greater than the horizontal direction, and the vertical shear strength is about 1.15 times that of the horizontal direction; the shear strength of the East and the west is little different, and the north and south direction is slightly larger than the east west direction. It can be preliminarily considered that the Ma Lan loess in this area is vertical. The mechanical properties of joints and porous structures are more obvious.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU444

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本文編號：1978135