【作者】 马栋；

【导师】 王梦恕； 谭忠盛；

【作者基本信息】 北京交通大学 ， 地下工程， 2012， 博士

【摘要】 在复杂岩溶地区修建长大隧道是一个世界性的技术难题。岩溶隧道的设计施工中存在一系列的风险和困难：富水高水压地段的隧道衬砌受力规律很难把握；施工阶段的突水、突泥也对施工安全和进度造成很大威胁；分布于路基面下的岩溶及衬砌外的高水压都给运营安全留下隐患。宜万铁路是我国铁路路网“八纵八横”主骨架之一,是川汉铁路(沪-汉-蓉)快速通道的重要组成部分,是百年来建设的重要通道,是连接我国东中部地区的重要交通纽带。宜万铁路穿越地区岩溶非常发育,岩溶地下水的水位、岩溶洞穴与岩溶管道的高程远低于当地排泄基准,使得本区的隧道工程总体处于深埋和高水压的大背景,深埋岩溶具有的高隐蔽性、高压性使得隧道施工非常困难和危险。论文紧密依托宜万铁路八座Ⅰ级风险岩溶隧道中的野三关、大支坪隧道深入研究深埋岩溶形成的条件、特征及对隧道施工运营的影响规律,在此基础上提出岩溶处治的原则和技术,主要研究内容和成果如下：(1)从资料调研和工程实践入手研究深部岩溶形成的条件、发育特点以及涌突水的机理,提出隧道所处岩溶地下水动力剖面分带位置及构造位置决定了隧道岩溶涌水在空间上的分布,并在此基础上建立了深埋岩溶涌突水模型。通过地表岩溶调查、示踪试验等手段对野三关隧道岩溶的发育特征进行了研究,分析了野三关隧道典型岩溶的发育情况及特征,并对其突水的地质因素进行了分析。(2)通过调研和现场实践研究了不同岩溶类型的水压、溶洞充填物性质、溶洞与地表的水力连通性等对隧道施工的影响,分析了岩溶突水的最可能工序,指出了高压富水充填溶腔对隧道施工的危害最大,并分析了隧道与溶洞间岩层破坏的机理；通过理论和数值分析提出了岩溶位置、规模对隧道施工的影响；提出隧道与溶洞之间的岩层真正能起阻水作用的是其中完整的岩层,隧道与溶洞之间的岩体厚度达到1倍的隧道直径时,溶洞对隧道围岩的变形速率影响较小；在经验类比、理论分析、数值试验基础上,紧密结合现场实践,提出了岩溶隧道掌子面揭穿溶洞时的安全岩盘厚度,并将其应用于野三关、大支坪隧道工程实践。(3)系统论述了岩溶隧道初始水压力计算方法,提出了岩溶隧道衬砌水压力计算方法,分析了注浆对衬砌水压力及排水量的影响规律,提出了合理的注浆范围；并通过完全模拟真实水土荷载的大型三维模型试验,研究了不同排放条件下衬砌水压的分布规律,提出了即使在全排水条件下,隧道衬砌仍承受由于水作用引起的部分水压力,在全排水情况下完全不考虑水压力的计算方法是不安全的。通过对现场监测数据分析及时掌握了施工过程中降雨量、溶腔涌水量及典型断面衬砌的水压特征,收集了通车后衬砌的水压极值数据,表明衬砌所受水压不大,低于设计值。提出了在长期运营中还应重视降雨量、排水量的变化与衬砌水压关系的研究。(4)在理论-实践-再理论-再实践的不断探索中,研究提出了岩溶隧道施工超前地质预报的范围,提出了岩溶隧道超前地质预报原则；提出了突水防治原则、溶腔处治原则、安全施工原则、环境保护原则,提炼总结出一套系统的岩溶隧道处治技术；针对不同类型的岩溶,提出了合理处治各种类型岩溶的措施,为岩溶隧道的安全施工和运营提供了保障。(5)提出在岩溶地区,为了增设工作面,设置斜井的风险很大。通过工程实例说明,斜井将隧道不同含水层连通,造成斜井涌水量很大,给施工带来很大风险,经济投入很大。因此,岩溶或含水丰富地层在辅助导坑设置上,应摒弃斜井,而是设置平导,这在增加工作面、减少排水、降低施工风险方面优势极为突出。另外对于侵入隧道的富水岩溶,必须设置排放通道维持其流动体系,并将排放通道与泄水洞形成排水的永久结构体系,确保运营的长期安全。(6)野三关隧道、大支坪隧道地质之复杂,施工难度之大居宜万铁路8座Ⅰ级风险岩溶隧道之首,通过详细记录分析两座隧道处治高压富水充填溶腔的过程,用实例说明了针对高压富水溶腔,希望完全封堵的思路是行不通的,并提出了有效的技术措施,保证了岩溶隧道的顺利建成,并为以后类似工程的建设提供了宝贵的第一手资料。更多还原

【Abstract】 It is a world-wide technically difficult problem tunneling across Karst district. There are a series of problem with the design and construction of Karst tunnel. It is difficult to master the load distribution under high water pressure. The water-inrush and mud-inrush threat the safety of workers and equipments. Karst caves under bed and high water pressure is hidden danger to railway operation. Yi-Wan railway line is one of the main railway net in China, it is also one important part of the express route from Shanghai to Sichuan. The railway passes across Karst-develop district where Karst action generally lags behind Qingjiang valley cutting. The water level or the height of Karst cave and Karst tube is far below the drainage base level. So tunnels in this district are deep buried and under high water pressure. The invisible and enormous damage with deep buried Karst makes tunnel construction extremely difficult.Taking Yesanguan and Dazhiping Karst tunnels as examples, the forming condition, character of deep buried Karst caves and their impact on tunnel construction and railway operation are studied. The Principle and technique for dealing with karst is put up based on the study. The main contents and achievements are:(1) The forming condition, developing character and water-inrush mechanism of deep buried karst is studied by document analysis and engineering practice. The opinion is put up that the karst hydrodynamic zoning and tectonic position control the space distribution of water inrush. Based on this opinion, the karst water-inrush models are established. By ground surface karst investigation and tracer test, the karst developing character of Yesanguan tunnel is studied, and the geological factors causing water-inrush are analyzed.(2) By document investigation and engineering practice, the effect of karst type (including water pressure, the feature of cave filling, the hydro-connection with ground) on tunnel construction is studied. The possible process of water-inrush is analyzed. By this study, it is pointed out that karst caves with high water and complex filling are most dangerous to tunnel construction, and the broken mechanism of rock between tunnels and caves is analyzed. By theoretic and numeric method, the effect of position and scale of the karst cave on the tunnel is studied, it is put up that only the intact rock between tunnels and caves can play a role to stop water inrush. When rock depth between tunnels and rocks is bigger than the tunnel’s diameter, the effect of cave on tunnel deformation is very small. Based on empirical analogy, theoretical analysis and numerical test, the safe rock depth between tunnel driving face and cave is put up combined with engineering practice, it is used in Yesanguan and Dazhiping tunnel construction.(3) The method for calculating original water pressure of karst tunnel is thoroughly discussed. The paper puts up the method to calculate water pressure on lining for karst tunnel, and analyzes the law of grouting on water pressure on lining and discharge, puts up the suitable grouting range. By three dimensional model test that laying the tunnel into true water and soil circumstance, the distribution rule of water pressure on lining during different drainage condition is studied, and the viewpoint is put up that tunnel lining bearing the load from seepage even under the condition of total drainage, and the traditional calculation method of no considering water pressure on lining during total drainage is not proper. By analyzing the situ monitoring data, the amount of precipitation, the water-inrush quantity and the water pressure character on lining of the typical section are mastered. In this paper, the ultimate data of water pressure of typical section is collected, it indicates that the water pressure is far below the design value after one year’s operation, but still we must pay attention to the study of the relation between the amount of precipitation, the water-inrush quantity and the water pressure.(4) By the constant exploration of theory-practice-theory-practice, a systematic principle and technique to deal with karst disaster is refined. The suitable range of advance geology forecast during construction and the maximum design value of water pressure on lining are put up, and the achievements are used in practice. The paper puts up the principle of advanced geology forecast, the principle of guarding against water-inrush, the principle of cave treating, the principle of safe construction, the principle of protecting environment and the technique of treating karst caves. For different type of karst disaster, there is corresponding technique to deal with, it provides safeguard for tunnel construction and operation.(5) It is put up that it is with high risk to excavate inclined shaft in Karst district. It is illustrated that inclined shafts connect different aquifer, bring large amount of water inflow and cause high risk to construction, and it is uneconomical. So, inclined shafts should be abandoned in design and the pilot should be advocated in karst district or other aquifer, and it is with big advantage in adding excavation face, reducing water inflow, decreasing construction risk. For karst intruding into tunnel and with water pressure, the drainage conduit must be installed to maintain its flowing state. And the conduit should be connected with drainage tunnel permanently so as to safeguard the operation.(6) The construction difficulty of Yesanguan and Dazhiping tunnel is the most among the eight tunnels with high risk because of the complex geology. By thoroughly recording and analyzing the process of dealing with the two caves with high water pressure and complex filling, it is illustrated that it is not practical trying to seal it for this type of cave. A series of effective measure is put up to safeguard tunnels’ construction. All this provides valuable material at first hand for similar project.更多还原