盾构出洞水平冻结解冻温度场三维有限元分析

为揭示人工冻土解冻规律,对某地铁区间隧道盾构出洞水平冻结工程融化温度场进行了三维数值模拟分析,并研究了土体导热系数、比热容、含水率和环境温度等因素变化对人工冻土融化温度场的影响.计算结果表明:冻结帷幕解冻所需热量主要来自于与隧道管片和混凝土槽壁接触的大气;解冻过程可为负温阶段、相变阶段和正温阶段,土体温度在负温阶段上升较快,相变阶段上升速度明显变缓,进入正温区后土体温度回升速度再次增大;负温阶段受比热容的影响比较显著,含水率增大引起相变阶段明显延长,导热系数和环境温度变化对三个阶段都有显著影响.为跟踪注浆控制融沉提供了理论依据.

3-D finite element analysis of melting temperature field in hield tunnelinghorizontal freezing reinforcing engineering

To reveal the thaw ing law o f art ificially f rozen soil, the melt ing temper ature f ield of horizo ntalfr eezing eng ineer ing project in the const ruct ion of subw ay hield tunneling w as studied w ith the 3-D numericalsimulation analysis. T he ef fect of the thermal conduct ivity , the specific heat capacity and the w aterco ntent of so il and the environmental temperature on the melting temper ature field of art ificially fr ozen soilw er e studied. The r esul ts show that mo st of the heat fo r thaw ing f reezing curtain is fr om air co ntact ingw ith tunnel segment and concrete groo ve wall , the thaw ing process includes the negat ive-temperaturestage, the phase t ransit io n stage and the posit ive-temperature stage, and that the so il temperature increasesfast in the neg ativ e-temperature stage, slow s dow n in the phase t ransit ion stag e and increases fast ag ainin the posit ive-temperature stag e. The result s also show that the ef fect o f specif ic heat capacity on the soiltemperature in negat ive-temper ature stage is significant . T he increase of w ater content in so il causes theextension of the phase t ransit io n stage, and that the inf luence o f thermal conductivity and env ironmenttemperature on all the three stag es is significant . The f inding s provide theoret ical support to gro ut ingt racking and thaw sett lement cont rolling .