本文選題：黏性土　切入點(diǎn)：動(dòng)三軸試驗(yàn)　出處：《浙江科技學(xué)院》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：為了解決城市交通擁堵問題,我國(guó)修建了許多地鐵隧道工程。在東部軟黏土地區(qū)修建的地鐵隧道,在車輛振動(dòng)荷載作用下會(huì)產(chǎn)生較大運(yùn)營(yíng)期沉降,引起襯砌管片開裂,上部結(jié)構(gòu)沉降等問題。本文針對(duì)軟黏土地區(qū)地鐵隧道長(zhǎng)期沉降問題開展研究,首先對(duì)杭州地區(qū)黏土通過室內(nèi)動(dòng)三軸試驗(yàn)研究了動(dòng)力特性,其次采用電鏡掃描試驗(yàn)和PCAS圖像處理技術(shù),對(duì)該黏土三軸試驗(yàn)前后的土體微觀結(jié)構(gòu)進(jìn)行了定性、定量的分析,闡述了土體宏觀變形和微觀孔隙變化的關(guān)系。通過把室內(nèi)動(dòng)力學(xué)試驗(yàn)結(jié)果、數(shù)值建模與沉降經(jīng)驗(yàn)擬合公式相結(jié)合,分別計(jì)算了土體累計(jì)塑性變形引起的沉降和累計(jì)孔壓消散引起的沉降。得到了一些關(guān)于杭州地區(qū)黏土和地鐵運(yùn)營(yíng)期長(zhǎng)期沉降有意義的結(jié)論:(1)杭州地區(qū)飽和黏土的動(dòng)應(yīng)變屬于穩(wěn)定發(fā)展型;在動(dòng)荷載作用下累計(jì)應(yīng)變曲線隨振動(dòng)次數(shù)的發(fā)展呈現(xiàn)先快速發(fā)展后趨于穩(wěn)定的狀態(tài)。當(dāng)圍壓和振動(dòng)頻率一定時(shí),相同振次,動(dòng)應(yīng)變隨著動(dòng)荷載的增加而增加,最終穩(wěn)定發(fā)展,動(dòng)孔壓在不同動(dòng)應(yīng)力情況下也存在隨動(dòng)應(yīng)力增長(zhǎng)的現(xiàn)象。(2)對(duì)地鐵列車作用于鋼軌上的荷載進(jìn)行了簡(jiǎn)化和分析,得到與時(shí)間相關(guān)的振動(dòng)荷載曲線。(3)將杭州地鐵隧道運(yùn)營(yíng)期長(zhǎng)期沉降,分成累計(jì)塑性變形引起的長(zhǎng)期沉降和累計(jì)孔壓消散引起的長(zhǎng)期沉降兩部分。運(yùn)營(yíng)期總沉降量在前五年發(fā)展較快,運(yùn)營(yíng)十年之后總沉降量隨著時(shí)間的增加仍然在增加,但增長(zhǎng)速度非常緩慢,可以認(rèn)為達(dá)到了穩(wěn)定狀態(tài)。這時(shí),累計(jì)塑性變形所引起的沉降量占總沉降量的85%以上。(4)分析SEM照片,發(fā)現(xiàn)土體微觀顆粒的尺寸、排列、相互位置和形態(tài),會(huì)隨著動(dòng)荷載的不同而發(fā)生變化,循環(huán)荷載的頻率和動(dòng)應(yīng)力幅值對(duì)土體微觀單元結(jié)構(gòu)的影響十分明顯,并有較強(qiáng)的規(guī)律性,且該規(guī)律性和室內(nèi)動(dòng)三軸試驗(yàn)土樣的應(yīng)變發(fā)展規(guī)律相吻合。
[Abstract]:In order to solve the problem of urban traffic congestion, many subway tunnel projects have been built in our country. In this paper, the long-term settlement of subway tunnel in soft clay area is studied. Firstly, the dynamic characteristics of clay in Hangzhou are studied by dynamic triaxial test. Secondly, the microstructure of the clay before and after triaxial test was analyzed qualitatively and quantitatively by scanning electron microscopy and PCAS image processing technology. The relationship between the macroscopic deformation of soil and the change of micro-pore is expounded. By combining the results of indoor dynamic test, the numerical modeling and the empirical fitting formula of settlement are combined. The settlement caused by accumulated plastic deformation of soil and the settlement caused by cumulative pore pressure dissipation are calculated, respectively. Some meaningful conclusions on the long-term settlement of clay in Hangzhou area and subway operation period are obtained. The dynamic strain belongs to the stable development type; Under the action of dynamic load, the cumulative strain curve develops rapidly first and then tends to stable with the development of vibration times. When the confining pressure and vibration frequency are fixed, the same vibration times and dynamic strain increase with the increase of dynamic load, and finally develop stably. Dynamic pore pressure also exists the phenomenon of following dynamic stress growth under different dynamic stress.) the load of subway train acting on rail is simplified and analyzed. The time-dependent vibration load curve. It is divided into two parts: the long-term settlement caused by accumulative plastic deformation and the long-term settlement caused by accumulative pore pressure dissipation. The total settlement in the first five years develops rapidly, and after ten years of operation, the total settlement is still increasing with the increase of time. But the growth rate is very slow and can be considered stable. At this time, the settlement caused by the cumulative plastic deformation accounts for more than 85% of the total settlement.) by analyzing the SEM photos, we found that the size, arrangement, position and shape of the soil microscopic particles. The frequency of cyclic load and the amplitude of dynamic stress have obvious influence on the micro-element structure of soil, and have strong regularity. And the regularity is consistent with the strain development law of the dynamic triaxial test soil.
【學(xué)位授予單位】：浙江科技學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：U456.3;U231;TU433

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 王啟云;張家生;孟飛;陳曉斌;陳俊樺;;高速鐵路路基模型列車振動(dòng)荷載模擬[J];振動(dòng)與沖擊;2013年06期

2 鐘怡;;地鐵報(bào) 一種新的嘗試——中國(guó)大陸地鐵報(bào)發(fā)展史研究[J];新聞傳播;2013年01期

3 谷川;蔡袁強(qiáng);王軍;楊芳;胡秀青;;循環(huán)應(yīng)力歷史對(duì)飽和軟黏土小應(yīng)變剪切模量的影響[J];巖土工程學(xué)報(bào);2012年09期

4 趙春彥;周順華;袁建議;;地鐵荷載作用下疊交隧道長(zhǎng)期沉降的半解析法[J];鐵道學(xué)報(bào);2010年04期

5 朱啟銀;葉冠林;王建華;夏小和;;軟土地層盾構(gòu)隧道長(zhǎng)期沉降與施工因素初探[J];巖土工程學(xué)報(bào);2010年S2期

6 魏星;王剛;余志靈;;交通荷載下軟土地基長(zhǎng)期沉降的有限元法[J];巖土力學(xué);2010年06期

7 王田友;丁潔民;樓夢(mèng)麟;;地鐵運(yùn)行引起場(chǎng)地振動(dòng)的荷載與分析方法[J];工程力學(xué);2010年01期

8 溫日琨;王常晶;陳云敏;;交通荷載引起的靜偏應(yīng)力對(duì)飽和軟粘土變形影響[J];巖土力學(xué);2009年S2期

9 王常晶;溫日琨;陳云敏;;交通荷載引起的主應(yīng)力軸旋轉(zhuǎn)室內(nèi)試驗(yàn)?zāi)M探討[J];巖土力學(xué);2008年12期

10 邊學(xué)成;曾二賢;陳云敏;;列車交通荷載作用下軟土路基的長(zhǎng)期沉降[J];巖土力學(xué);2008年11期

相關(guān)博士學(xué)位論文 前1條

1 張曦;地鐵振動(dòng)對(duì)隧道周圍軟粘土微結(jié)構(gòu)影響及動(dòng)力特性研究[D];同濟(jì)大學(xué);2007年

相關(guān)碩士學(xué)位論文 前1條

1 黃耿彩;受擾動(dòng)地鐵隧道土體在列車周期性振動(dòng)荷載下位移規(guī)律的研究[D];同濟(jì)大學(xué);2007年

，

本文編號(hào)：1636730