摘要
【目的】受制冷媒介温度差异以及被冻地层与冻结管距离差异的影响,多冷媒联合双排管冻结壁的非均匀性较为显著,为了合理评价该类冻结壁的安全性,需开展考虑非均质性的多冷媒人工冻结壁弹塑性应力分析。【方法】选取距离1/4管距处的冻结壁作为特征截面,将该截面上的温度分布曲线等效成三段一次函数形式,并将冻结壁视为随温度成线性变化的非均质材料,分别基于4种冻土屈服准则,推导得出多冷媒联合双排管非均质冻结壁弹塑性应力解析表达式。基于该解析表达式,对多冷媒冻结壁的受力特性进行计算,并将该计算结果与均质冻结壁计算得出的结果进行对比。【结果和结论】研究发现:(1)在盐水-二氧化碳联合双排管冻结壁中,径向应力随着相对半径r的增加而上升,环向应力在不同冻结区间(Ⅰ、Ⅱ、Ⅲ)表现出不同的变化趋势。(2)基于均质冻结壁计算理论,弹性极限状态的冻结壁的环向应力最大值出现在冻结壁内侧,弹塑性状态的冻结壁的环向应力最大值出现在弹塑性分界面处,塑性极限状态的冻结壁的环向应力最大值出现在冻结壁最外侧;而基于非均质冻结壁计算理论,冻结壁环向应力最大值始终出现在冻结壁分区界线(r=2)处。(3)在考虑非均质特性后,冻结壁的弹性极限承载力降低1.8%,而塑性极限承载力提高8.1%。在弹塑性状态下,对应相同塑性区相对半径,非均质冻结壁具有更高的承载力,且这种现象随着塑性区相对半径的增大而愈发明显。研究成果对富水地层多冷媒联合冻结帷幕的设计具有重要的参考价值。
Objective Affected by the temperature difference of the refrigerant and the distance difference between the frozen formation and the freezing pipes,the heterogeneity of the multi-refrigerant combined double-row-pipe frozen wall is more significant.In order to evaluate the safety of such frozen wall reasonably,the elastic plastic stress analysis should be carried out for the artificial frozen wall with multi-refrigerant considering the heterogeneity.Methods The frozen wall at 1/4 pipe distance was selected as the characteristic section.Then,the temperature distribution curve on this section was equivalently converted to three linear functions,and the frozen wall was regarded as a heterogeneous material that changes linearly with temperature.On this basis,the analytical expression of plastic-elastic stress of multi-refrigerant combined double-row-pipe heterogeneous frozen wall was derived according to four kinds of frozen soil yield criteria.Based on the analytical expression,the mechanical characteristics of the multi-refrigerant frozen wall were calculated,and the calculated results were compared with those of the homogeneous frozen wall.Results and Conclusions The study indicates that:(1)The radial stress increases with the increase of the relative radius r,and the circumferential stress shows different trends in different frozen intervals(Ⅰ,Ⅱ,Ⅲ)in the brine-CO_(2) combined double-row-pipe frozen wall.(2)Based on the calculation theory of the homogeneous frozen wall,the maximum circumferential stress appears on the inner side of the frozen wall in the elastic limit state,at the elastic-plastic interface of the frozen wall in the elastic-plastic state,and at the outermost side of the frozen wall in the plastic limit state.However,based on the calculation theory of heterogeneous frozen wall,the maximum circumferential stress always occurs at the partition boundary of frozen wall(r=2).(3)With consideration to the heterogeneity,the elastic ultimate bearing capacity of the frozen wall decreases by 1.8%,while the plastic ultimate bearing capacity increases by 8.1%.In the plastic-elastic state,the heterogeneous frozen wall has higher bearing capacity compared with that in the same relative radius of plastic zone,and this phenomenon becomes more obvious with the increase of the relative radius of the plastic zone.The research results have important reference value for the design of multi-refrigerant combined freezing curtain in water-rich strata.
作者
王彬
梁秀玲
张子浩
蔡海兵
荣传新
WANG Bin;LIANG Xiuling;ZHANG Zihao;CAI Haibing;RONG Chuanxin(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan 232001,China;Postdoctoral Research Station,China Coal Mine Construction Group Co.,Ltd.,Hefei 230091,China;Henan Key Laboratory of Underground Engineering and Disaster Control,Henan Polytechnic University,Jiaozuo 454000,China)
出处
《煤田地质与勘探》
EI
CAS
CSCD
北大核心
2024年第9期106-120,共15页
Coal Geology & Exploration
基金
国家自然科学基金项目(52378384)
安徽省自然科学基金项目(2308085ME188)
安徽省博士后科学基金项目(2022B635)
河南省地下工程与灾害防控重点实验室开放基金项目(KFKT 2023-06)。
关键词
人工地层冻结法
双排管冻结壁
多冷媒联合冻结帷幕
非均质
屈服准则
弹塑性分析
artificial ground freezing method
double-row-pipe frozen wall
multi-refrigerant combined freezing curtain
heterogeneity
yield criteria
elastic-plastic analysis
作者简介
第一作者:王彬,1991年生,男,山东沂水人,博士(后),副教授。E-mail:wbingoo@163.com。
