本文關鍵詞： 松散堆積體地層 大斷面隧道 工法適應性 安全施工技術　出處：《中南大學》2014年碩士論文　論文類型：學位論文

【摘要】：本論文結合杉樹坳隧道松散堆積體淺埋段工程實踐,通過進洞初期出現的大變形和塌方事故以及后期處理技術方案優(yōu)化及實施效果分析,開展了堆積體淺埋段大斷面隧道不同工法適應性研究,為類似軟弱圍巖隧道施工提供技術支持和經驗,主要研究內容包括： 1.基于杉樹坳隧道施工階段安全風險評估,判定隧道總體施工安全風險等級為Ⅱ級(中度風險),而隧道洞口過堆積體淺埋段發(fā)生洞口失穩(wěn)、坍塌事故的風險等級為Ⅲ級(高度風險),應制定風險消減措施以確保安全施工。 2.通過對兩種不同工法適應性數值計算結果對比分析,表明在松散堆積體淺埋地層中CD法相較于三臺階七步開挖法,更有利于控制圍巖變形。 3.三臺階七步開挖法在Ⅵ級軟弱圍巖中應用時,不同臺階分部施工轉換過程中,在上臺階和中臺階施工過程中支護結構內力和變形增幅較大,易引發(fā)掉拱、大變形或塌方事故；而CD工法由于增設豎向臨時支撐,與三臺階七步開挖法相比各分部施工過程中支護結構內力和變形量增幅明顯較小,有利于保證淺埋段隧道圍巖支護結構體系的穩(wěn)定性。 4.總結松散堆積體淺埋地層塌方原因及隧道CD工法的施工技術管理要點,順利完成了洞口段100m長松散堆積體淺埋段的施工,為類似工程提供了經驗和參考。
[Abstract]:In this paper, combined with the engineering practice of shallow buried section of loose accumulation body in the tunnel of Zaoshuao tunnel, through the large deformation and collapse accident in the early stage of tunnel entry and the optimization of the post-treatment technical scheme and the analysis of the effect of the implementation. The adaptability study of different engineering methods for large section tunnel of shallow buried section of accumulation body is carried out, which provides technical support and experience for tunnel construction of similar soft surrounding rock. The main research contents are as follows:. 1. Based on the assessment of the safety risk in the construction stage of the tunnel, it is determined that the overall construction safety risk grade of the tunnel is grade 鈪，

本文編號：1515382