【摘要】：為了分析盾構(gòu)進(jìn)出洞時(shí)隧道端部土體的失穩(wěn)破壞模式,為端部土體合理加固范圍的確定提供理論依據(jù),基于顆粒流分析程序(PFC),對(duì)砂層盾構(gòu)隧道端部土體的失穩(wěn)破壞過程和機(jī)理進(jìn)行了數(shù)值分析,并采用FLAC3D程序進(jìn)行對(duì)比驗(yàn)證。根據(jù)土體滑動(dòng)規(guī)律,給出一種對(duì)數(shù)螺旋線與直線組合的滑動(dòng)破壞模式,運(yùn)用顆粒流計(jì)算數(shù)據(jù)對(duì)滑動(dòng)面進(jìn)行曲線擬合,并進(jìn)行相關(guān)性分析和顯著性檢驗(yàn),得到顆粒摩擦因數(shù)取不同數(shù)值時(shí)的土體滑移面曲線方程。研究結(jié)果表明:隧道端部連續(xù)墻破除后,土體先在洞門附近發(fā)生局部破壞,隨后土體顆粒松動(dòng)破壞向內(nèi)部發(fā)展,顆粒逐步發(fā)生位移重定向,最終在土體內(nèi)部形成了一條顯著的滑動(dòng)破壞面,若隧道埋深較淺,滑動(dòng)面將延伸貫通至地表;隨著土體強(qiáng)度的增高,土體滑移直線傾角變大,對(duì)數(shù)螺旋線初始半徑變小,土體破壞范圍相應(yīng)變小,端部土體越穩(wěn)定,反之,端部土體滑移范圍就會(huì)變大,穩(wěn)定性變差;端部土體經(jīng)過局部加固后,土體變形較小,內(nèi)部不能形成滑動(dòng)面,端部土體穩(wěn)定性得以提高。
[Abstract]:In order to analyze the failure mode of the end soil of the tunnel when shield machine enters and leave the tunnel, it provides a theoretical basis for the determination of the reasonable reinforcement range of the end soil. Based on the particle flow analysis program (PFC), the failure process and mechanism of soil in the end of shield tunnel in sand layer are analyzed numerically, and the results are compared and verified by FLAC3D program. According to the sliding law of soil mass, a sliding failure mode combining logarithmic helix and straight line is presented. The sliding surface is fitted by the calculated data of particle flow, and the correlation analysis and significance test are carried out. The slip surface curve equation of soil is obtained when the particle friction coefficient is different. The results show that after the end of the tunnel continuous wall is broken, the soil first occurs local failure near the portal, and then the loose failure of the soil develops to the interior, and the displacement reorientation of the particles occurs step by step. Finally, a significant slip failure surface is formed in the soil. If the tunnel is shallow, the sliding surface will extend to the surface. With the increase of soil strength, the slope of slip line becomes larger, and the initial radius of logarithmic spiral becomes smaller. The failure range of the soil becomes smaller and the end soil is more stable. On the contrary, the slip range of the end soil will become larger and the stability will become worse. After the end soil is partially strengthened, the deformation of the soil is smaller and the sliding surface cannot be formed inside. The stability of the end soil can be improved.
【作者單位】： 魯東大學(xué)土木工程學(xué)院;北京交通大學(xué)土木與建筑工程學(xué)院;中國中鐵隧道股份有限公司;
【基金】：國家自然科學(xué)基金項(xiàng)目(51478213,51278237)
【分類號(hào)】：U455.43
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本文編號(hào)：2291357