地铁联络通道人工冻结帷幕设计计算方法研究

Study on Design and Calculating Methods of Artificial Freezing Curtain on Metro Connected Passage-Way Project

人工冻结法始于19世纪,该技术首先应用于矿山立井工程,是深立井建设的主要工法。近年来,随着地下铁道建设的迅速发展,人工冻结法已成为软土地区地铁盾构隧道水平联络通道建设中常用的加固方法之一。以往人工冻结帷幕的设计主要建立在矿井建设的基础之上,而城市地下工程与矿井在施工深度、施工方法和受力状态都存在着很大的差异,因而需要对人工冻结法在城市地下工程中的相关设计方法进行研究。首先采取强度控制法,应用框架结构力学模型计算满足冻土强度要求所需的冻土壁厚度的设计方法进行研究;基于二维稳态温度场分布理论,考虑冻结温度的影响,提出水平联络通道冻结管布置方式(包括冻结管间距和布置形式)的确定方法;根据单位体积岩土放出的热量等于冻结管吸收的热量并结合立井冻结的经验公式提出不同冻结管布置形式下冻结时间的计算方法。最后,结合工程实例,对地铁联络通道人工冻结帷幕进行设计。

Artificial freezing method was first applied in mine shaft engineering in the 19th century which developed into the main method of deep vertical shaft construction. In recent years, with the rapid devel- opment of underground railway construction, artificial freezing method has been a common reinforcement method of metro connected passage - way construction in soft soil area. The design of previous artificial freezing curtain primarily built on the basis of the construction of the mine shaft engineering, while there are significant differences in depth, methods and stress state between the construction of the urban under- ground and the mine shaft engineering. So we need to study the artificial freezing method in underground engineering. First, according to the control theory of intensity , the paper gives the general method of calculating the thickness of the frozen soil wall, that is using the framework of structural mechanics model calculates the thickness of frozen soil wail which can meet the requirement of the structure. Based on two - dimensional steady-state temperature field distribution theory, the paper proposes the method of the ar-rangement of freezing pipes, including the space and layout of them. In the premise of considering the heat flow, according to the heat released of per unit volume of soil equal to the heat absorbed by freezing pipes, in combination with an empirical formula in mine shaft engineering, the paper proposes the method of calculating the freezing time under different arrangements of freezing pipes. Finally, combined with en-gineering examples, the paper designs the artificial freezing curtain of the metro connected passage-way.