【作者】 胡群芳；

【导师】 黄宏伟；

【作者基本信息】 同济大学 ， 结构工程， 2006， 博士

【摘要】 地层的随机分布与变异性是影响隧道工程建设的重要风险因素，国内外很多学者对其进行了大量研究。论文以上海市科委2004年重大科技攻关项目——隧道工程的施工监控与预警、报警系统及风险管理系统研究(04dz12021)为依托，以上海长江隧道工程为研究对象，讨论了江底长大隧道工程的地层随机分布和土体变异特征，提出了相应的分析理论和计算方法，并以此为基础将其应用到上海长江隧道工程风险分析中。论文主要研究内容及成果如下： (1) 结合上海长江隧道工程建设概况资料，将其与国内外的重要水底隧道工程进行了系统的对比研究，重点分析了上海长江隧道工程的建设特点和难点——超大直径(世界第一)、高水压作用(最高水压达0.6MPa)、一次性长距离(盾构施工掘进长度达7.5km)施工、穿越复合土层等，并依次对上述特点和难点进行了详细的对比分析和重点讨论，列出了工程建设过程中的重要风险因素。 (2) 系统分析了地质勘查及土层的不确定性，并对地质钻孔得到的土层信息进行了构成分析和术语定义，建立了土层、土组的随机分布概率统计模型。由于地层由不同的土层组成，不同土层之间存在相互关联或联合，利用所建统计模型，建立了沿隧道工程轴线上场地不同点处的土层、土组的随机分布概率计算模型。结合上海长江隧道工程场地内的164个地质钻孔资料，对其场地区域内不同土层、土组的随机分布概率进行了统计，并计算了各土层、土组沿隧道轴线方向上的随机分布规律，明确了工程各区间段的土层随机分布特征。 (3) 通过引入地质统计学理论和随机Markov链模型，将土层的随机分布剖面状态转换成土层的状态转移计数矩阵，建立土层随机转移状态预测模型，并针对一维的Markov链模型，将其拓展成条件一维Markov链模型，由此建立了二维空间土层随机转移状态预测模型。结合上海长江隧道工程地质勘查资料，编写了相应的计算程序对工程中的重点区域土层分布状态进行了预测模拟。 (4) 考虑土体参数的不确定性来源，即：空间变异性和系统不确定性，详细分析了土层参数的系统变异值和空间变异值的计算方法。通过引入工程风险分析理论，分析了土体参数估计的不确定性因素，利用极大似然理论建立了土体样本试验次数与其参数取值的风险损失函数关系，并讨论建立了土体参数试验次数的估算方法和土工试验风险效益计算。根据上海长江隧道工程土工试验数据资料，对其场地内的土体各物理、力学参数指标进行变异性分析。 (5) 分析了盾构隧道衬砌结构建设期主要风险因素和破坏类型，列出了衬砌结构风险评价等级标准，采用故障树理论建立了衬砌结构建设期风险估计的系更多还原

【Abstract】 Tunneling works were characterized by high degree of uncertainty. These uncertainties stem from two major problems: the geologic conditions are never known exactly and particular for deep and long crossing river tunnels; preconstruction information may be very sparse. And the first uncertain factor may have greater impaction on tunneling. It is known that the geologic uncertainty about spatial variability of stratum and soil is one of the biggest problems on which were focused by many researchers at home and abroad during the last three decades. Due to the inherent uncertainties including soil and groundwater conditions, there might be significant cost overrun and time delay risks in tunneling works. So the dissertation focused on the research of the spatial variability of stratum and soil, and established some theoretical models and calculating methods for application in risk analysis of tunneling works. The dissertation is supported by Shanghai Municipal Science and Technology Commission (Grant No.04dz12021) and its research achievement can be applied in the risk analysis on construction of Shanghai Yangtze River. Some main works and results about the dissertation were listed as follow.(1) Shanghai Yangtze River Tunnel is the biggest worldwide tunnel project. The dissertation firstly gave a brief introduction about the project and listed some most difficult construction problems in tunneling, such as the biggest diameter, high water pressure up to 0.6MPa, all long distance about 8.95km and multilayered shield excavation. Those key risk-induced factors were analyzed and discussed in detail by comparing with some other bigger tunnels all over world. Furthermore, all the important risks of the project were identified and summarized based on some engineering practice and experience.(2) Some uncertainties about geological site investigation were analyzed. And some terms about stratum like soil family and soil cluster were defined firstly. In order to calculate the stochastic distribution about strata, some methods were established to calculate probability of different soil clusters, soil families and soil types. Because of the co-existence of a soil type with many other soil types in a given site, the probability of co-existence of different soil types was measured against the soil with other soils under different clusters. Then we can get the probability of finding a soil type at a target point along tunnel alignment with respect to the clusters and soils that exist in the neighborhood of some boreholes. On the更多还原