發(fā)布時(shí)間：2019-06-20 01:38

【摘要】：2013年蘭州市委市政府為全面實(shí)現(xiàn)“三年有效緩解、五年明顯改善”的暢交通目標(biāo),將暢交通工程列為服務(wù)人民的“一號(hào)工程”,圍繞既定的“一橫、三環(huán)、九縱”骨干路網(wǎng)體系,在城市核心區(qū)實(shí)施184個(gè)上跨下穿工程,同時(shí)地鐵一號(hào)線、二號(hào)線一期工程全線展開(kāi),大批量的工程建設(shè)產(chǎn)生了大量的基坑工程問(wèn)題。由于下穿工程大多位于城市中心區(qū)域的交通擁堵路段,場(chǎng)地狹窄、周邊環(huán)境錯(cuò)綜復(fù)雜,處理不當(dāng)就會(huì)引發(fā)安全問(wèn)題。本文以蘭州市第一個(gè)下穿工程——天水路下穿讀者大道車行地道基坑工程為研究背景,以理論分析、現(xiàn)場(chǎng)實(shí)測(cè)及數(shù)值模擬相結(jié)合的方法,利用MIDAS/GTS對(duì)基坑開(kāi)挖的實(shí)際過(guò)程進(jìn)行模擬分析,研究了基坑在實(shí)際開(kāi)挖過(guò)程中支護(hù)結(jié)構(gòu)的水平位移、周圍地表沉降變形以及基坑坑底隆起變形的發(fā)生發(fā)展規(guī)律。同時(shí),研究分析了開(kāi)挖工序、樁體埋深、樁體直徑、樁間距、鋼支撐間距等因素對(duì)圍護(hù)結(jié)構(gòu)水平位移、周圍地表沉降、基底隆起的變形影響規(guī)律,論文主要的研究?jī)?nèi)容及成果有:(1)查閱大量資料文獻(xiàn)對(duì)國(guó)內(nèi)及蘭州地區(qū)基坑工程穩(wěn)定性和變形規(guī)律的研究現(xiàn)狀進(jìn)行了總結(jié),闡述了基坑穩(wěn)定性計(jì)算、變形機(jī)理及變形計(jì)算的理論。(2)利用基坑穩(wěn)定性分析計(jì)算軟件對(duì)依托工程圍護(hù)結(jié)構(gòu)的整體穩(wěn)定性、抗隆起穩(wěn)定性、抗傾覆穩(wěn)定性進(jìn)行了驗(yàn)算分析,分析結(jié)果表明人工挖孔灌注樁加橫向鋼支撐的支護(hù)結(jié)構(gòu)能夠保證該基坑在開(kāi)挖過(guò)程中的安全穩(wěn)定。(3)數(shù)值模擬分析結(jié)果表明:在基坑開(kāi)挖深度不大,未架設(shè)鋼支撐之前,支護(hù)結(jié)構(gòu)的水平位移表現(xiàn)為懸臂式位移;架設(shè)鋼支撐后,支護(hù)結(jié)構(gòu)的水平位移則發(fā)展為拋物線形位移。周圍地表的沉降變形表現(xiàn)為距圍護(hù)墻越遠(yuǎn),沉降越小的勺形分布,在距圍護(hù)墻約0.4-0.7倍的基坑開(kāi)挖深度范圍內(nèi),地表沉降值最大。(4)監(jiān)測(cè)結(jié)果與數(shù)值模擬結(jié)果曲線對(duì)比分析表明:模擬曲線與實(shí)測(cè)曲線的變化規(guī)律相一致,且受到施工及降水等因素的影響,實(shí)測(cè)樁身最大水平位移為9.6mm,遠(yuǎn)小于警戒值30mm,說(shuō)明此設(shè)計(jì)偏于安全。(5)對(duì)各影響因素的模擬分析表明:改變樁體埋深對(duì)周圍地表沉降的影響不大,但對(duì)圍護(hù)結(jié)構(gòu)的水平位移影響較大;在一定的范圍內(nèi),增加樁體直徑可以有效的減小圍護(hù)結(jié)構(gòu)的水平位移以及周圍地表的沉降變形,但對(duì)基底隆起變形的影響卻十分有限;樁間距的增大會(huì)引起圍護(hù)結(jié)構(gòu)水平位移的增大,從而進(jìn)一步引起周圍地表沉降變形的影響范圍和變形量。
[Abstract]:In 2013, in order to fully realize the smooth traffic goal of "three years of effective mitigation and five years of obvious improvement", the Lanzhou Municipal CPC Committee and Municipal Government listed the smooth traffic project as the "No. 1 project" to serve the people. Around the established "one horizontal, third ring, nine vertical" backbone network system, 184 upper-span and down-crossing projects were carried out in the urban core areas, while the whole line of the first phase of Metro Line 1 and Line 2 was launched. A large number of engineering construction has produced a large number of foundation pit engineering problems. Because most of the underpass projects are located in the traffic congestion sections in the central area of the city, the site is narrow and the surrounding environment is complex, which will lead to safety problems. In this paper, based on the research background of the foundation pit engineering of Tianshui Road, which is the first underpass project of Tianshui Road, the actual process of foundation pit excavation is simulated and analyzed by using the method of theoretical analysis, field measurement and numerical simulation, and the horizontal displacement of the supporting structure, the settlement deformation of the surrounding surface and the occurrence and development of the foundation pit bottom uplift deformation in the actual excavation process are studied. At the same time, the influence of excavation process, pile depth, pile diameter, pile spacing and steel support spacing on the horizontal displacement of enclosure structure, the settlement of surrounding surface and the deformation of foundation uplift is studied and analyzed. The main research contents and achievements of this paper are as follows: (1) the research status of stability and deformation law of foundation pit engineering in China and Lanzhou area is summarized, and the stability calculation of foundation pit is expounded. The deformation mechanism and the theory of deformation calculation are carried out. (2) the overall stability, uplift stability and overturning stability of the retaining structure relying on the engineering are checked and analyzed by using the software of foundation pit stability analysis. The analysis results show that the supporting structure of manual excavated cast-in-place pile and transverse steel support can ensure the safety and stability of the foundation pit during excavation. (3) the results of numerical simulation analysis show that the horizontal displacement of the supporting structure is cantilever displacement before the excavation depth of the foundation pit is small and the steel support is not installed. After the steel support is installed, the horizontal displacement of the supporting structure develops into a parabola displacement. The settlement and deformation of the surrounding surface shows that the farther away from the retaining wall, the smaller the spoon shape distribution, and the maximum surface settlement value is in the range of 0.4 脳 0.7 times the excavation depth of the retaining wall. (4) the comparison and analysis between the monitoring results and the numerical simulation results show that the simulation curve is consistent with the measured curve, and is affected by construction and precipitation. The maximum horizontal displacement of the measured pile is 9.6mm, which is much less than the warning value of 30mm, which indicates that the design is safe. (5) the simulation analysis of various influencing factors shows that changing the buried depth of the pile has little effect on the surrounding surface settlement, but has a great influence on the horizontal displacement of the enclosure structure. In a certain range, increasing the diameter of pile can effectively reduce the horizontal displacement of enclosure structure and the settlement and deformation of surrounding surface, but the influence on the deformation of foundation uplift is very limited, and the increase of pile spacing will lead to the increase of horizontal displacement of envelope structure, thus further causing the influence range and deformation of surrounding surface settlement and deformation.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU433;TU473.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

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本文編號(hào)：2502809