破碎千枚岩隧道开挖方法及支护结构体系研究

发布时间：2018-05-16 03:18

本文选题：破碎千枚岩 + 软岩隧道　；参考：《西南交通大学》2014年博士论文

【摘要】：随着我国西部大开发的逐渐深入,穿越高烈度、强震区等复杂地质条件下以千枚岩为代表的软岩隧道工程大量涌现,上述地区原有山体遭遇强震的揉搓损伤使得山区环境更加艰险,尤其在经历强震动力作用后,千枚岩岩体内部产生了大量隐性损伤,岩体完整性降低、透水性增强、表现出明显破碎松散特征,使得灾后重建过程中穿越该类岩体的工程实施难度进一步加大,各种灾害现象频发。隧道建设过程中该场区内施工期安全控制基准、工法及支护结构体系中关键参数的正确选取成为摆在业界学者面前的首要问题,至今也尚未形成统一的开挖及支护结构设计标准。因此,形成一套适应新近破碎千枚岩隧道的安全控制体系是确保未来西部高烈度区大量破碎千枚岩隧道安全施工的关键。论文以龙门山断裂核心影响区域的杜家山千枚岩隧道建设为工程背景,结合四川省交通科技项目课题“广甘高速公路隧道修建关键技术”开展研究。在广泛资料搜集与现场调研的基础上,主要采用理论分析、相似模型试验、数值模拟和现场试验等研究手段,对新近破碎千枚岩岩体的典型性状及隧道变形特征与成因机制进行了深入剖析,并以此为依托,针对该场区条件下隧道施工期安全控制基准管理体系、施工工法及支护结构体系中的关键设计参数进行详细研究,取得主要成果如下：1、揭示了破碎千枚岩低强度、低密度、弹性波速衰减强、渗透性高及架空现象明显等基本特征,分析了该场体条件下隧道施工期围岩-支护变形特征及失稳破坏的主要演变方式。针对隧道失稳断面变形及结构受力特点,从岩体基本特性、变形破坏特征及影响因素等方面分析了结构失稳的成因机制,并揭示毛洞状态洞室极限位移。2、通过对依托工程隧址区大量典型失稳案例的统计分析,探明了破碎千枚岩隧道安全控制基准建立的主要关联指标及管理指标控制值,根据隧道变形的演变规律,拟定了初期支护安全位移、裂损位移、正常使用极限状态位移、承载能力极限状态位移的划分标准,将安全位移、裂损位移纳入安全控制基准管理等级的划分中。3、结合隧道-地层模拟试验系统与数值模拟,分析了隧道埋深、工法、断面形式、支护强度等管理指标与安全基准之间的关联性影响,揭示了各影响因子下结构的破坏规律以及对应的极限位移；以此为基础,结合变形监测值的统计分析,确定了以娟云母千枚岩为代表的V级软岩安全控制值,并根据各安全控制值的划分与选取,建立了隧道以“台阶法”开挖为主的不同埋深档施工期安全控制基准,同时提出合理预留变形值。4、利用现场试验及有限元计算方法分析了破碎千枚岩隧道在采用目前山岭隧道主流工法下围岩及支护结构的变形及力学特性,探讨了各工法下两者间的相互作用机理,揭示了各工法对千枚岩地层的适宜性与技术可行性,并确定了隧道适宜工法。同时对适宜工法在采取不同循环进尺、台阶高度比、核心土宽高比等参数开挖后结构的变形及力学特性进行了比较分析,提出了适宜工法关键参数。5、开展了破碎千枚岩隧道基于支护参数优化的力学特性相似模型试验,探明了不同喷砼厚度、拱架间距、锚杆长度及排列、二次衬砌厚度等因素对隧道结构变形及力学特性的影响规律,确定了支护结构体系中的关键参数。6、对提出的支护参数在依托工程典型围岩段开展了现场试验研究,通过对测试数据的系统分析,论证了不同支护结构对破碎千枚岩隧道的支护效果,揭示了结构变形及受力的长期演变规律,对比分析了有、无系统锚杆结构的力学特征,探明了锚杆支护作用效果,实现对衬砌结构安全性的综合评判。新近破碎千枚岩岩体的物理力学特点与一般地区软岩有较大区别,两者施工期安全控制体系存在较大差异。论文研究成果将为破碎千枚岩隧道的结构设计提供理论依据和实用方法,同时为我国西部高烈度区未来大量破碎千枚岩隧道的建设提供参考。
[Abstract]:With the development of the Western China, the soft rock tunnels, represented by phyllite in the complex geological conditions such as high intensity and strong earthquake area, have springing up. The rubbing damage caused by strong earthquakes in the original mountain areas in the above areas makes the environment more difficult and dangerous, especially in the phyllite rock mass after the strong vibration force. With the recessive damage, the integrity of rock mass is reduced, the permeability is enhanced, and the characteristics of breakage and looseness are obvious. It makes the engineering implementation difficulty of crossing the rock mass in the process of post disaster reconstruction and the frequent occurrence of various disasters. The key parameters in the construction period of the tunnel construction are the key parameters in the construction period and the support structure system. The correct selection has become the first problem in front of the scholars in the industry. So far, a unified design standard for excavation and support structure has not been formed. Therefore, a set of safety control systems adapted to the newly broken phyllite tunnel is the key to ensure the safe construction of a large number of broken thousand rock tunnels in the high intensity area of the West. The paper is in Longmen mountain. The construction of the Dujiashan phyllite tunnel construction is the project background, combined with the project of Sichuan transportation science and technology project "the key technology of the Guangzhou Gansu highway tunnel construction". On the basis of the extensive data collection and field investigation, it mainly adopts the theoretical analysis, the similar model test, the numerical simulation and the field test. In this paper, the typical characters of the newly broken phyllite rock mass, the deformation characteristics and the formation mechanism of the tunnel are deeply analyzed. On this basis, the key design parameters in the construction method and the supporting structure system are studied in detail, and the main results are obtained, such as the key design parameters in the construction period of the tunnel under the condition of the field. 1, the basic characteristics of the broken phyllite, such as low intensity, low density, strong attenuation of elastic wave velocity, high permeability and obvious aerial phenomenon, are revealed. The deformation characteristics of surrounding rock support and the main evolution mode of unstable failure are analyzed under the condition of the tunnel construction. The cause mechanism of structural instability is analyzed, and the ultimate displacement.2 of the tunnel is revealed. Through the statistical analysis of a large number of typical instable cases in the tunnel site, the main related indexes and the control values of the management indexes of the broken phyllite tunnel safety control datum are explored. According to the evolution law of the tunnel deformation, the safety displacement of the initial support, the displacement of the crack, the normal use of the limit state displacement, the limit state displacement of the bearing capacity, the safety displacement and the crack displacement are included in the division of the safety control standard management grade.3, and the tunnel is combined with the tunnel stratum simulation test system and the numerical simulation, and the tunnel is analyzed. The relationship between the management indexes of the buried depth, the engineering method, the section form, the support strength and other management indexes and the safety datum, reveals the destruction law of the structure and the corresponding limit displacement under the influence factors. On this basis, the safety control value of the V grade soft rock represented by Juan mica phyllite is determined by the statistical analysis of the deformation monitoring value. According to the division and selection of the safety control values, the safety control datum of the different buried depth in the construction period of the tunnel with "step method" is established, and the reasonable reserved deformation value.4 is put forward. The surrounding rock and support of the broken phyllite tunnel under the main main work method of the mountain tunnel are analyzed by the field test and the finite element calculation method. The deformation and mechanical properties of the structure are discussed and the interaction mechanism between the two methods is discussed. The suitability and technical feasibility of the various methods for the phyllite strata are revealed, and the suitable method of the tunnel is determined. At the same time, the deformation of the structure after the excavation is taken with the parameters of different cycle footage, step height ratio, core soil width and height ratio. And the mechanical characteristics are compared and analyzed, the key parameter.5 is put forward, and the similar model test of mechanical characteristics is carried out based on the support parameters optimization of the broken phyllite tunnel. The influence of the different thickness of the concrete, the distance of the arch, the length and arrangement of the bolt, the thickness of the two lining and so on, on the deformation of the tunnel structure and the mechanical properties of the tunnel are explored. The key parameter.6 in the supporting structure system is determined. The proposed support parameters are studied in the typical surrounding rock section of the support project. Through the systematic analysis of the test data, the supporting effect of different support structures on the broken phyllite tunnel is demonstrated, and the long-term evolution law of the structural deformation and stress is revealed, and the comparison is made. The mechanical characteristics of the non systematic bolt structure are analyzed. The effect of the bolt support is explored and the comprehensive evaluation of the safety of the lining structure is realized. The physical and mechanical characteristics of the newly broken phyllite rock mass are different from the soft rock in the general area. There are great differences in the safety control system during the construction period. The research results of the paper will be broken to a thousand. It provides a theoretical basis and practical method for the structural design of Mei Yan tunnel, and provides reference for the construction of a large number of fractured phyllite tunnels in Western China.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U455.4

【参考文献】