本文選題：滲透系數(shù) + 深基坑��； 參考：《廣西大學(xué)》2015年碩士論文

【摘要】：針對土體滲透系數(shù)和孔隙比沿深度非線性變化且與土體的應(yīng)力狀態(tài)有關(guān)的實際情況,本文基于修正劍橋模型,建立了土體滲透系數(shù)與孔隙比、孔隙比與土體應(yīng)力之間的函數(shù)關(guān)系,并利用ABAQUS及其二次開發(fā)平臺,建立了考慮孔隙比和滲透系數(shù)隨應(yīng)力變化影響的深基坑降水開挖數(shù)值模型,并對深基坑降水開挖引起的支護結(jié)構(gòu)內(nèi)力、位移以及坑內(nèi)外土體的位移展開了研究。主要研究內(nèi)容和結(jié)果如下：(1)建立孔隙比隨應(yīng)力變化、滲透系數(shù)隨孔隙比變化的函數(shù)關(guān)系,并編寫了相應(yīng)的用戶子程序,建立了考慮孔隙比和滲透系數(shù)隨應(yīng)力變化影響的深基坑降水開挖數(shù)值模型。經(jīng)驗證發(fā)現(xiàn)該模型用于基坑降水開挖分析是合理可靠的。(2)在滲透系數(shù)不變的前提下,對比分析考慮與不考慮孔隙比變化結(jié)果發(fā)現(xiàn),考慮孔隙比變化的墻體最大水平位移、地表最大沉降分別比后者大約28%、110%,深層土體沉降以及開挖深度以上的土體水平位移也比后者的明顯較大,但最大坑底隆起比后者的小約31%。(3)在考慮孔隙比變化的前提下,對比分析考慮與不考慮滲透系數(shù)變化的結(jié)果發(fā)現(xiàn),考慮滲透系數(shù)變化的墻體最大水平位移、最大地表沉降、坑底最大隆起、墻體最大彎矩(絕對值)分別比后者相應(yīng)的結(jié)果小約30%、25%、10%、12%；前者的深層土體沉降以及開挖深度以上的土體水平位移比后者的明顯較小。(4)對比分析同時考慮孔隙比和滲透系數(shù)變化與兩者均不考慮的結(jié)果發(fā)現(xiàn),同時考慮孔隙比和滲透系數(shù)變化的墻體最大水平位移、坑底最大隆起、墻體最大彎矩(絕對值)分別比兩者均不考慮時相應(yīng)的結(jié)果小約10%、38%、5%,但坑外土體沉降明顯比后者的大。(5)深基坑降水開挖的數(shù)值模擬中考慮孔隙比和滲透系數(shù)隨應(yīng)力變化能較好地在反映降水的影響�？梢�,在深基坑降水開挖的數(shù)值模擬中考慮孔隙比和滲透系數(shù)隨應(yīng)力狀態(tài)變化是很有必要的。
[Abstract]:In this paper, based on the modified Cambridge model, the permeability coefficient and porosity ratio of soil are established in view of the nonlinear variation of soil permeability coefficient and void ratio along the depth and related to the stress state of the soil. Based on the functional relationship between void ratio and soil stress and using Abaqus and its secondary development platform, a numerical model for dewatering excavation of deep foundation pit considering the effect of porosity ratio and permeability coefficient on stress is established. The internal force, displacement and the displacement of soil inside and outside the pit caused by dewatering excavation of deep foundation pit are studied. The main research contents and results are as follows: (1) the functional relationship of porosity ratio with stress and permeability coefficient with porosity ratio is established, and the corresponding user subprogram is written. A numerical model for dewatering excavation of deep foundation pit considering the effect of porosity ratio and permeability coefficient on stress is established. It is found that the model is reasonable and reliable for the analysis of dewatering and excavation of foundation pit. Under the premise of constant permeability coefficient, the maximum horizontal displacement of wall considering the variation of void ratio is found by comparing the analysis results with and without considering the variation of void ratio. The maximum settlement of the surface is about 28 / 110, respectively. The settlement of deep soil and the horizontal displacement of soil above the excavation depth are also significantly larger than those of the latter, but the maximum uplift of the bottom is about 31% smaller than that of the latter.) under the premise of considering the variation of porosity, By comparing the results of considering and disregarding the change of permeability coefficient, it is found that the maximum horizontal displacement, maximum surface settlement, maximum uplift of the bottom of the wall with the change of permeability coefficient are considered. The maximum bending moment (absolute value) of the wall is about 30% less than the corresponding result of the latter, respectively; the deep soil settlement of the former and the horizontal displacement of the soil above the excavation depth are obviously smaller than those of the latter) and the porosity ratio and permeability are taken into account simultaneously. The change of permeability coefficient and the result that neither of them were taken into account found that, At the same time, considering the change of porosity ratio and permeability coefficient, the maximum horizontal displacement of the wall and the maximum uplift of the bottom of the wall are taken into account. The maximum bending moment (absolute value) of the wall is about 100.38 and 55.But the settlement of soil outside the pit is obviously larger than that of the latter.) in the numerical simulation of dewatering excavation of deep foundation pit, porosity ratio and permeability coefficient are taken into account with stress. The change can better reflect the influence of precipitation. Therefore, it is necessary to consider the variation of void ratio and permeability coefficient with stress state in the numerical simulation of dewatering excavation of deep foundation pit.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU463

【參考文獻】

相關(guān)期刊論文 前1條

1 曹力橋;鄭剛;;坑內(nèi)降水對軟土地區(qū)深基坑坑底隆起影響有限元分析[J];巖土工程學(xué)報;2008年S1期

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本文編號：2009501