【作者】 夏彬伟；

【导师】 李晓红；

【作者基本信息】 重庆大学 ， 采矿工程， 2009， 博士

【摘要】 层状岩体由于受层理结构面的影响而具有明显的横观各向同性,其变形破坏特征更为复杂。国内外学术界对层状岩体各向异性已进行了大量的研究,目前对于层理条数众多但每条层理力学性质不完全相同的薄层状岩体,一般采取逐一分析每条层理,其过程过于复杂繁琐,且个别参数取值仍然依靠工程经验,无法客观的描述层状岩体破坏机理,只有选择合适的屈服准则及合理确定强度参数随岩层倾角(与最大主应力的夹角)的变化规律才能从根本上解决该问题。故针对此问题,开展深埋隧道层状岩体变形破坏机理相关研究具有重要的理论意义和工程实用价值。论文在国家自然科学基金专项基金创新群体基金项目(No.50621403)以及国家自然科学基金重点项目“隧道与地下空间工程结构物的稳定性与可靠性(No.50334060)”的资助下,以共和隧道为示范工程,运用理论分析、物理模型实验、数值模拟和现场测试等手段,对共和隧道大埋深段层状岩体的围岩变形破坏机理、锚杆支护力学效应及围岩-支护结构的变形特征等内容进行了研究,其主要研究成果有:①在总结和探讨国内外学者提出的层状岩体经验型连续介质破坏准则基础上,结合层状岩体力学特性,考虑层面方向和最大主应力方向两个影响因素,提出了共和隧道层状岩体横观各向同性破坏准则;采用汇编语言VC++6.0实现了横观各向同性弹塑性本构关系的算法,并嵌入FLAC3D有限差分数值分析软件接口中实现数值运算。②根据共和隧道岩体的力学参数,以砂和重晶石为骨料,汽油为稀释剂,分别以环氧树脂、硅橡胶、松香为粘结剂,再添加其他的辅助材料研制了3种不同力学性质的相似材料,均具有可模性、连续弹性模量和抗压强度,可满足模拟3种不同力学性质岩体的要求。③根据共和隧道砂质页岩的力学性质,运用相似理论,构筑不同倾角层状岩体的物理模型,研究了高应力条件下层状岩体围岩应力变化及变形破坏过程特征,确定了层状岩体在垂直于层面方向上围岩应力变化规律及破坏形态,揭示了深埋隧道层状岩体的破坏机理;物理模型实验研究得到的围岩应力变化规律及破坏特征与数值模拟分析的结果基本一致,同时也验证了横观各向同性弹塑性本构模型的正确性。④运用物理模型实验研究了毛洞、常规锚杆和加长锚杆模型围岩应力分布特征,分析了不同长度锚杆加固下围岩的力学效应,研究结果表明了锚杆加固区围岩形成“压应力场”,改善了围岩内部受力状态,从而在宏观上揭示了锚杆加固围岩力学效应机理。⑤针对深埋隧道层状岩体变形破坏特征,按相似原理,构筑了普通系统锚杆物理模型和优化系统锚杆物理模型,运用物理模型实验应变测试技术、内窥摄影技术和锚杆轴向应力测试技术,对比分析了两种不同锚杆支护下物理模型的围岩应力分布、围岩破坏特征和锚杆轴向应力分布,表明了不同部位锚杆加固围岩力学效应不同,揭示了层状岩体中锚杆加固的作用机理,为优化设计锚杆提供了可靠的科学理论依据。⑥结合共和隧道地应力测试,对隧址区层状岩体山体地应力进行了反演研究,并运用监控量测技术和数值模拟手段,分析了层状岩体各向异性力学特征对隧道围岩变形和稳定性的影响,为类似工程设计和施工提供了可靠的科学依据。更多还原

【Abstract】 Layered rock mass has obvious characteristic of transverse isotropy due to bedding plane, and its failure properties are highly complicated. The anisotropic property of layered rock mass has been concentrated through many decades, and the method of one-by-one analysis is still popular for those thinly layered rock mass with massive different beddings, but it is well known that this method has some problems such as great dependence on engineering practice and low accuracy while high workload. Thus the efficient path for solving the problem is to create a better yield criterion and determine the strength parameter for different rock strata.The dissertation, Sponsored by National Natural Science Foundation of China (Grant No. 50621403;50334060), took Chongqing Gong-he tunnel as an engineering example and studied the failure mechanism of surrounding rock and the correlation with bolt support system by using the methods of theoretical analysis, modeling test, numerical simulation and in situ test, some helpful conclusions were arrived as follows.Firstly, a new failure criterion for transversely isotropic rock mass was proposed with consideration of bedding plane orientation and major principal stress, and the corresponding algorithm, arrived through VC++6.0, can be easily embedded into the software FLAC3D for the geotechnical calculation.And also, three new kinds of model materials with the property of normability, continuous elastic modulus and compressive strength were made for different types of rock mass, in which, sand and barite as main materials, gasoline as diluents, epoxy resin, silicone rubber and rosin as binders, of course, there exist other auxiliary materials.Thirdly, surrounding rock deformation and failure process of layered rock mass in high geo-stress was reappeared through the physical models with different dip angle of rock stratum, and the stress change and failure discipline in the direction of vertical to bedding plane was definitely determined.Fourthly, The stress distribution of surrounding rock in tunnels with no support, common bolts, and long bolts were peered through physical models test, the results show that bolt reinforcement area is a compressive stress field.Additionally, by using strain testing, endoscopic photography and bolt axial stress testing on physical models, the geo-stress redistribution and failure characteristic were studied by comparing two physical models with common systematic bolts and optimized systematic bolts. And the bolt axial stress distribution discipline was also found in different areas, which will be helpful for the revision of bolt design.Last but not least, the initial in situ stress of the mountain massif was inverse analyzed by field test, meanwhile, the influence of anisotropic properties of layered rock mass on the deformation and stability of the tunnel were also evaluated by means of monitoring, measurement and numerical simulation.更多还原