摘要
根据测温孔在冻结壁温度场检测中存在的不足和高密度电阻率法勘探的特点,进行了高密度电阻率法检测冻结壁温度场的可行性探讨。在初始含水量和密度与原位土一致的情况下,采用高密度电阻率法中的温纳四极、温纳偶极和温纳微分3种装置,分别对上海地铁四号线的粉砂土进行了在30^-30℃条件下的导电性试验研究。结果表明,视电阻率随温度降低而增大,导电性随温度的降低而减弱,导电性与温度密切相关;在温度高于-4℃条件下,粉砂土的电阻率随温度变化相对较小,温度低于-4℃时,粉砂土电阻率随温度变化较明显;同时,在30℃≥t>-4℃、-4℃≥t>-10℃、-10℃≥t≥-30℃三个温度段分别拟合出相关度较高的温度—电阻率回归方程。试验表明高密度电阻率法检测冻结壁是可行的,可为今后上海乃至长江三角洲地区类似土层采用冻结法施工时检测冻结壁的发育状况提供参考。
In view of the shortcomings of the hole for measuring temperature in monitoring the temperature field of freezing wall and the peculiarity of the high density resistivity method,this paper studied the feasibility of applying the high density resistivity method to monitoring the temperature field of freezing wall.Under the condition of initial water content and density of the test soil similar to that of the undisturbed soil,the electrical conducting characteristics of silty soil in No.4 Line of Shanghai Metro System were studied with three resistivity methods（Wenner-α、Wenner-β and Wenner-γ） at 30～-30℃.Some phenomena have been observed： First,trends between the variation of apparent resistivity and the variation of the temperature by three high density resistivity methods are very consistent,namely,apparent resistivity of silty soil will augment（or electrical conducting characteristics will become weak）when its temperature falls,and electrical conducting characteristics are close to temperature;second,when temperature overtops-4℃,the range of resistivity diversification of silty soil is relatively narrow when temperature changes;thirdly,when temperature is below-4℃,the resistivity of silty soil will change obviously when temperature changes;fourthly,three high fitting degree regression equations of temperature-resistivity were fitted,they were applicable to 30℃≥t〉-4℃,-4℃≥t〉-10℃,-10℃≥t≥-30℃ respectively by each high density resistivity method.All the above results show that the high density resistivity method is suitable for monitoring the temperature field of freezing wall,and can provide a reference for testing the development of freezing wall in similar soil layers when the artificial ground freezing method is employed in Shanghai and even the Yangtze River Delta.
出处
《物探与化探》
CAS
CSCD
北大核心
2010年第5期647-651,共5页
Geophysical and Geochemical Exploration
基金
安徽省优秀青年科技基金项目(08040106828)
安徽高校省级科学研究基金(KJ2009B099Z)
关键词
高密度电阻率法
粉砂土导电特性
上海地铁
冻结法
冻结壁检测
high density resistivity method
electrical conducting characteristics of silty soil
Shanghai Subway
freezing method
freezing wall test
