本文選題：黃土基坑 + 瞬態(tài)滲流��； 參考：《西安建筑科技大學(xué)》2015年碩士論文

【摘要】：近年來(lái),黃土地區(qū)城市興建產(chǎn)生的黃土基坑問(wèn)題越來(lái)越多,本文結(jié)合西安地鐵三號(hào)線大雁塔站主體結(jié)構(gòu)基坑工程,運(yùn)用瞬態(tài)滲流理論對(duì)黃土基坑降水及降水對(duì)沉降的影響進(jìn)行了數(shù)值模擬,并與現(xiàn)場(chǎng)監(jiān)測(cè)數(shù)據(jù)進(jìn)行了對(duì)比分析。主要內(nèi)容如下:(1)黃土層中含水量增加能夠降低黃土的強(qiáng)度繼而降低黃土基坑的整體穩(wěn)定性,基坑的安全性降低,為了保證開(kāi)挖的安全性,故需要在基坑的開(kāi)挖過(guò)程中采取措施降低地下水位。(2)運(yùn)用瞬態(tài)滲流理論對(duì)西安地鐵三號(hào)線大雁塔站主體結(jié)構(gòu)基坑工程的降水過(guò)程及降水對(duì)沉降的影響進(jìn)行動(dòng)態(tài)模擬。結(jié)果表明:靠近止水帷幕底部的基坑外節(jié)點(diǎn)水頭變化最大,并且在前一周變化幅度較大,隨后變化速度平緩,水頭隨時(shí)間大致呈線性變化,規(guī)律與現(xiàn)場(chǎng)水位觀測(cè)數(shù)據(jù)較接近。基于比奧固結(jié)原理,計(jì)算了實(shí)際工程降水引起的沉降,沉降值與監(jiān)測(cè)值相差較小。降水20天后,距基坑5m處沉降計(jì)算值為2.36cm,實(shí)際監(jiān)測(cè)值為2.69cm。(3)運(yùn)用瞬態(tài)滲流理論研究了止水帷幕的作用效果以及管井與止水帷幕的距離對(duì)降水效果的影響。結(jié)果表明:坑外側(cè)地下水繞過(guò)止水帷幕從其底部進(jìn)入管井,從而延長(zhǎng)了滲流路徑。設(shè)置止水帷幕可大幅降低坑外側(cè)水頭損失,進(jìn)而有效減小固結(jié)沉降。降水20天后,由上至下基坑外各觀測(cè)節(jié)點(diǎn)水頭損失,距離越大坑外水頭損失越小,對(duì)于減小固結(jié)沉降越有利。
[Abstract]:In recent years, there are more and more problems of loess foundation pit caused by urban construction in loess area. This paper combines with the excavation of the main structure of Dayan Pagoda Station on Xi'an Metro Line 3. The transient seepage theory is used to simulate the influence of dewatering and precipitation on the settlement of loess foundation pit, and the results are compared with the field monitoring data. The main contents are as follows: (1) the increase of water content in the loess soil layer can reduce the strength of loess and then reduce the overall stability of loess foundation pit, and the safety of foundation pit is reduced, in order to ensure the safety of excavation, Therefore, it is necessary to take measures to reduce the groundwater level during the excavation of the foundation pit.) the transient seepage theory is used to simulate the dewatering process and the influence of the precipitation on the settlement of the main structure foundation pit of Dayan Tower Station of Xi'an Metro Line No. 3. The results show that the outside nodal head of the foundation pit near the bottom of the waterproof curtain has the largest change, and the variation range is large in the previous week, then the change speed is gentle, the water head changes linearly with time, and the law is close to the field water level observation data. Based on the Bio consolidation principle, the settlement caused by actual engineering precipitation is calculated, and the difference between the settlement value and the monitoring value is small. After 20 days of precipitation, the calculated value of settlement is 2.36 cm and the actual monitoring value is 2.69 cm. 3) the effect of the waterproof curtain and the distance between the pipe well and the waterproof curtain on the effect of precipitation are studied by using the transient seepage theory. The results show that the underground water at the outside of the pit bypasses the curtain and enters the pipe well from the bottom, thus prolonging the seepage path. Water-stop curtain can greatly reduce the head loss of the outside of the pit, and then effectively reduce the consolidation settlement. After 20 days of precipitation, the head loss of the observation nodes outside the foundation pit from top to bottom is reduced, the larger the distance is, the smaller the head loss is outside the pit, which is more favorable to reduce the consolidation settlement.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU753.66;TU433

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