基于ISM和模糊故障树的铁路黄土隧道塌方风险分析

研究如何对铁路黄土隧道塌方风险事故进行管理控制,先从地质因素、施工方法因素、监控量测因素和施工管理因素分析了黄土隧道塌方事故的成因。接着依据铁路行业隧道风险评估指南矿山法隧道施工风险因素列表,识别影响兰渝铁路某黄土隧道项目塌方的18项主要风险因素。然后运用系统工程解释结构模型方法(ISM)分析项目各风险因素间的相互关系,得出影响该隧道项目塌方的直接原因为施工扰动过大、支护不及时、拱脚悬空时间过长和信息反馈处理不及时。底层原因则为开挖方式、特殊地质条件。在上述基础上建立项目塌方事件模糊故障树模型,进行模糊定量分析,得到项目塌方事件发生的模糊概率和关键风险因素的模糊重要度。结果表明,实例黄土隧道项目塌方事故风险概率很大,地质因素、开挖方法等对塌方事故影响最大。解释结构模型方法能揭示各风险要素间的不确定性因果关系,有利于把握事故发生机理,模糊数能客观地描述风险事件的发生概率,增强故障树诊断方法的可靠性。

重载铁路黄土隧道水泥土挤密桩地基加固技术研究

隧道通过水泥土挤密桩在重载铁路砂质湿陷性新黄土隧道现场施工中的应用,验证了水泥土挤密桩在隧道有限空间中的适用性,采用非振动方式有效地控制了对隧道施工安全的影响。通过单桩承载力现场试验,表明在大断面重载铁路黄土隧道中,水泥土挤密桩隧底加固作用良好,对控制地基沉降和消除湿陷性作用明显,为类似地质重载铁路隧道基底加固提供借鉴。

基于数值模拟的黄土隧道施工地表变形分析与控制

基于某黄土隧道三台阶七步开挖法三维数值分析,提出黄土隧道开挖对地表横向最大影响范围约为3倍洞径,其中1倍洞径范围内影响较大,纵向最大影响范围约为2倍洞径,其中1倍洞径范围内影响较大,可对在此范围内的地表建筑拆除及加固;指出大管棚对控制地表变形有重要作用,明确了大管棚对地表变形影响作用在总变形量的20%以上;最后,将数值计算结果与工程实施后量测数据对比,侧证了计算结果的正确性,并找出两者差距的具体原因及应对措施.

浅埋黄土隧道施工方法及支护受力研究

本文以神延铁路十五标段及W6标段共四座黄土隧道施工及应力监测为切入点,对浅埋黄土隧道施工方案及施工中突出的技术问题,支护与土体间接触应力分布规律及引起结构变形原因进行了分析和探讨,对今后类似隧道的安全施工和支护结构设计具有一定的参考作用。

干阳沟隧道0号斜井挑顶方案比选和优化

以新建铁路山西中南部铁路通道干阳沟隧道0号斜井工程为例,详细介绍了富水黄土隧道斜井挑顶正洞3套施工方案的具体步骤和施工控制难点、要点,通过多方面对比,最终选定了导洞法施工方案,并在施工中取得了良好效果,为今后类似隧道挑顶施工积累了经验。

Key Techniques for the Construction of High-Speed Railway Large-Section Loess Tunnels

The successful completion of the Zhengzhou-Xi＇an high-speed railway project has greatly improved the construction level of China＇s large-section loess tunnels, and has resulted in significant progress being made in both design theory and construction technology. This paper systematically summarizes the tech- nical characteristics and main problems of the large-section loess tunnels on China＇s high-speed railway, including classification of the surrounding rock, design of the supporting structure, surface settlement and cracking control, and safe and rapid construction methods. On this basis, the key construction tech- niques of loess tunnels with large sections for high-speed railway are expounded from the aspects of design and construction. The research results show that the classification of loess strata surrounding large tunnels should be based on the geological age of the loess, and be determined by combining the plastic index and the water content. In addition, the influence of the buried depth should be considered. During tunnel excavation disturbance, if the tensile stress exceeds the soil tensile or shear strength, the surface part of the sliding trend plane can be damaged, and visible cracks can form. The pressure of the surrounding rock of a large-section loess tunnel should be calculated according to the buried depth, using the corresponding formula. A three-bench seven-step excavation method of construction was used as the core technology system to ensure the safe and rapid construction of a large-section loess tunnel, following a field test to optimize the construction parameters and determine the engineering measures to stabilize the tunnel face. The conclusions and methods presented here are of great significance in revealing the strata and supporting mechanics of large-section loess tunnels, and in optimizing the supporting structure design and the technical parameters for construction.