冻结加固盾构端头土体温度场数值分析  

Numerical Analysis of Soil Thermal Field in Freezing Reinforcement of Shield Arriving

作　　者：袁云辉[1] 杨平[1] 

机构地区：[1]南京林业大学土木工程学院,江苏南京210037

出　　处：《地下空间与工程学报》2010年第5期1053-1059,共7页Chinese Journal of Underground Space and Engineering

基　　金：江苏省六大人才高峰项目资助(2004);江苏省普通高校研究生科研创新计划(CX09S_015Z)

摘　　要：在人工冻结加固盾构到达端头土体施工过程中,土体温度是关系到冻土帷幕发展情况以及确定盾构机推进时机的重要参数。以南京地铁二号线集庆门车站北端头盾构进洞冻结加固工程为背景,利用大型有限元数值分析软件建立数学模型对冻结和自然解冻温度场进行计算,研究了多圈水平冻结条件下温度空间分布及温度随时间变化规律,并对左线开挖后垂直冻结管停冻和不停冻两种方案对温度场的影响进行对比,研究表明:采用多圈水平冻结并合理布置冻结圈径可以显著加快冻结壁的形成,从而缩短工期;自然解冻时存在两个解冻锋面,其中管片散热对解冻影响较大;自然解冻时温度上升速率先快后慢,而解冻锋面推进速度则越来越快;在左线开挖后可以停止左、右线洞门之间垂直冻结管的冷媒循环,同样能够保证右线冻结壁厚度达到设计要求。During the construction process of artificial soil freezing,soil temperature is an important parameter related to improvement of frozen wall and shield driving time.Taking the artificial soil freezing construction for the arriving of shield machine in the north end of Ji Tsing-men station of Nanjing No.2 Metro Line as its background,ADINA Finite Element Calculation Software is applied to compute the thermal field for freezing and nature thawing 2D model,and study the thermal spatial distribution and the variation laws of temperature with time.Also,two vertical freezing plans after shield excavation are compared.Studies have shown that freezing wall may be formed faster with multi-freezing-tube-cycles so to shorten the duration;During the process of nature thawing,two thawing faces existed,which segment radiating have more effect to thawing;temperature goes up fast in initial period and than becomes slow,the movement speed of thawing faces is in the opposite.After excavation of left tunnel,vertical freezing between two tunnels can be stopped to make it more economical.

关 键 词：盾构到达 人工水平冻结 温度场 自然解冻 数值分析 

分 类 号：TU443[建筑科学—岩土工程]