【作者】 管会生；

【导师】 高波；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2008， 博士

【摘要】 随着城市地铁建设的发展,国内已开始着手设计和研发国产盾构机。然而我国盾构设计理论尚不成熟,诸如盾构与地层之间的相互作用关系以及盾构上的荷载对盾构行为的影响等研究相对滞后。其次是国产盾构机的关键参数-推进力与刀盘扭矩的确定还没有形成一整套系统全面的计算理论模型。当地质条件和隧道直径变化时,这些参数很难确定,缺少必要的理论依据。因此,开展盾构机关键力学参数和力学行为的计算模型研究,其目的就是为盾构机的开发和国产化打下理论基础,为盾构的设计、选型和性能参数的确定提供必要的理论依据。本文的研究成果和主要内容如下:(1)通过对刀盘扭矩构成要素的系统分析,建立了新的刀盘扭矩计算的理论模型。提出了应考虑在模型中增加一些对刀盘的实际扭矩构成影响的新的要素,即,刀盘背面渣土的摩擦阻力扭矩、刀盘旋转时刀盘开口内土柱的剪切摩擦阻力矩以及刀盘构造柱的搅拌力矩,并对各扭矩分量进行了数学公式推导,通过与工程实测数据的对照分析对模型进行了验证。该计算模型为盾构机刀盘驱动扭矩参数的选择和正确确定提供了一定的理论依据。(2)基于盾构工程实际和现场测量数据,对刀盘扭矩计算的理论模型进行了实例计算。通过对刀盘扭矩的构成、各影响因素扭矩分量的大小和所占比例的计算,分析了影响刀盘扭矩的主要因素,同时分析了模型参数(地质条件、施工参数、刀盘结构以及刀具参数等)对刀盘扭矩的影响,为盾构的设计、选型和工程运用提供了理论指导。(3)建立了新的盾构推进力计算理论模型,运用力学原理和数学方法重新对盾构刀盘正面推进阻力和盾壳外围摩擦阻力进行了计算公式推导,以取代惯用的简化计算公式,使推力计算更精确,影响因素考虑的更全面;该模型全面系统地表征了盾构的推进力与盾构机的尺寸、土层的层别、厚度、容重、内聚力及内摩擦角等参数间的定量关系,为盾构机推力参数的选择和正确确定提供了理论依据。(4)为了有效地实现对盾构的行为控制,建立了反映盾构行为(位移、偏转角)、地层参数和盾构千斤顶推力三者之间关系的铰接式盾构力学行为的计算理论模型,该模型为盾构机的方向控制提供了新的思路。(5)研究了盾构的行为与土的相互作用关系。通过有限元模型,分析了盾构位移与盾壳外围法向土压力的作用关系,并获得了地层变形与土压力之间关系的地层反力曲线,为铰接式盾构力学行为的计算模型研究建立一定的理论基础。(6)盾尾是盾壳中最薄弱的结构。基于荷载结构法推导出了盾尾在各荷载单独作用下的弯矩和轴力计算公式。同时,应用盾尾与周围地层相互作用的多弹簧支点的平面应变有限元计算模型对上述公式进行验证。(7)分析了盾构掘进过程中刀盘刀具磨损的原因和影响因素,提出了刀具的掘进距离寿命和磨耗系数的概念及计算方法,得出了刀具磨损量T与掘进距离寿命L的预测曲线。更多还原

【Abstract】 As the rapid development of subway constructions in cities,designing and developing shield machines in China is at starting phase,and so a systematic theory for designing the shields has not been developed.As a result,research levels on many aspects are behind the Western,such as interactions between the shield and ground and between loads and mechanical behaviors of the shield.In addition,few existing models can systematically predict the key parameters of the shield-machine-jack thrust and cutter torque.As the change of the geological conditions and diameter of a tunnel in excavating,it’s difficult to determine the key parameters.The reason for this is that there are few theoretical models to describe the key parameters.In the present study,we study interaction between shield and ground.The purpose for the study is to found a theoretical basis for developing and manufacturing shield machines in China and for designing and selecting types of shields,associated with correctly choosing the parameters of the machine.Some achievements were made in the present study as follows:1.The influence factors of cutter torque were studied systematically, and a new prediction model for the cutter torque had been developed. The model shows that those new factors influencing on the cutter torque should be taken into account,i.e.,the frictional resistance torque on the back of cutterhead and the shear resistance torque of the muck in hatch of cutterhead and mixing round torque of the cutter head’s beam and The calculating formulae of those torque components in the model were deduced.Comparisons between predicted and observed data verify the validation of the model.This prediction model found a fast theoretical basis in determining the cutter torque of the shield.2.Bsed on shield engineering practice and measuring field data,a example has done to calculating cutter torque by the model.Main factors influencing on cutter torque have been studied by analyzing composition of cutter torque,magnitude of torque components and it’s proportion in total torque.It also been studied for parameters in model to influence on cutter torque,which have provide theoretical guide for the type selection,design of shield and it’s application.3.A prediction model on the jack thrust of the shield has been developed. The new calculating formulae were deduced by using mechanics theory and math method to the thrust resistance on the face of cutter head and on the shell of shield in the model.They replace simplified calculating formulae before.So the accuracy for predicting the jack thrust in the new model is higher than the existing models,more influence factors in assessing the jack thrust is accounted for.The relationships between the jack thrust of the shield and some parameters were expressed systematically in the model,i.e.,the size of the shield,layers and thickness for each layer,density and friction angle of the soils,etc.This prediction model found a fast theoretical basis in determining the Jack thrust of the shield.4.In order to control the behavior of shield availably,a model of mechanical behaviors of the articulated shield has been developed.The model expresses three relationships of behavior of the articulated shield,ground properties and shield mechanisms(jack thrust),which have provide a new way to control shield direction.5.The interaction between the behaviors of the shield and ground deformation has been studied.Additionally,the interaction between the ground displacement and earth pressures acting on the shield periphery has been studied.The ground reaction curve is achieved by using 2D FEM analysis for the shield tunneling.It also founds a theoretical basis for developing a mechanical behavior model of the articulated shield6.Shield tail is most weak structure of shield skin.Based on loads-structure method,the calculating formulae of moment and axes force has been deduced for every single load acting on the shield tail. These calculating formulae have been verified by 2D plane strain FEM model with more spring fulcrums showing the interaction between shield and ground.7.The influence factors of cutter wear were studied in shield tunneling. The definition and calculation method for tunneling distance life of cutter and wear-tear coefficient were proposed.The prediction curve between the wearing value of cutter and excavation distance life were obtained.更多还原