地层适应性盾构模型试验设计方法初探

Study on design principle of shield machine applicable to different strata

盾构法施工已经广泛应用于城市地铁隧道、越江通道和地下管道等工程施工中,但是与不断改进的隧道施工技术相比,现有的盾构机设计理论尚不具有很好的地层适应性。为了改进盾构地层适应性设计理论和方法,有必要开展土体-盾构系统的基础试验研究。在此过程中,不可能将全部参数方案都作成样机一一通过现场对比试验来选定,这就需要利用模型试验来预测实物的性能。为此,需要建立模型试验的条件和被预测的实物所处的条件之间的某种关系,相似理论正是起到一种联系桥梁的作用。根据相似理论和模型试验方法,建立了土体—盾构机器之间的相似系统,并针对上海地区特定的软土地层,进行了相似模型试验方法的设计,即利用直径400mm模型盾构机来模拟直径为6340mm原型盾构机,通过在人工配制的模型土壤中进行模拟掘进,记录下试验过程中盾构机及土体变形的有关试验参数,并据此形成盾构机的工作参数和地层物理力学特性之间的地层适应性理论。

Shield tunnel machines have been widely used in the construction of metro tunnels, channels and underground pipelines. Compared with advanced construction technologies, current design theories of shield machine can not fit the properties of soil very well. In order to improve the design theory and principle applicable to soil-shield machine system, it is necessary to take more fundamental experiment research. In consideration of that it is impossible to do large quantities of field experiments, model tests should be needed to predict the performance of prototype. Therefore, the specific relationship between model and prototype should be investigated. According to similitude principle and model test method, the similitude rules of soil-shield machine system is investigated; and the design principle of similitude model test about soil-shield machine system is established. As an example, a prototype shield machine with diameter of 6 340 mm is simulated by a microtunnelling machine with diameter of 400 mm; the model machine will drive in artificial model soil; meanwhile, the results of machine working parameters and soil deformation will be recorded. Based on these data, it is possible to improve the design theory of shield machine to fit different soil grounds.