Abstract 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 (Wennerα、Wennerβ and
Wennerγ) 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 temperatureresistivity 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.
|