Calculation method of unfrozen water content based on thermal conductivity of frozen soil

Abstract

The invention provides an unfrozen-water content calculating method based on a frozen soil heat-conduction coefficient. The method comprises the following steps: determining a heat conduction coefficient lambda of a saturated frozen soil sample with dry density of Rhod under negative temperature, drying the soil sample and determining a heat conduction coefficient ks of the soil sample under negative temperature; converting the dry density as Rhod and proportion of soil skeleton in frozen soil in bulk volume as Vs; calculating the volume ratio of unfrozen-water in frozen soil; calculating the proportion of the soil skeleton and the ice body in the frozen soil; and calculating the unfrozen-water content Wu in the frozen soil. The method has characteristics of direct viewing and convenient calculating, and provides means for calculating the unfrozen-water content. By comparing calculating value and actual measurement value, the prediction error provided by the calculating method is within 12.2%. The precision increase can greatly increase the calculating precision of the unfrozen-water content, and provides the calculating convenience of a temperature field in frozen soil engineering.

Description

technical field [0001] The invention belongs to the field of unfrozen water calculation in the field of frozen soil engineering, in particular to a calculation method for unfrozen water content based on the thermal conductivity of frozen soil, which can be used to obtain the unfrozen water of frozen soil on the premise of known thermal conductivity of frozen soil content. Background technique [0002] The unfrozen water content of frozen soil is an important basis for calculating the latent heat of phase change in the temperature field of frozen soil, and it is an important reason for the variation of thermal parameters of frozen soil with different negative temperatures. The unfrozen water content of frozen soil is also an important index to evaluate the freezing strength of frozen soil, and it is the key to study the water migration in frozen soil. In the temperature field prediction of frozen soil, the determination of the unfrozen water content of frozen soil is of grea...

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Problems solved by technology

Studies have shown that the actual measurement method is easily affected by the disturbance characteristics of frozen soil and instrument effects, and there is a significant difference in accuracy

Patent No. 201510749173.8 discloses a method for determining the unfrozen water content in the process of soil freezing by using specific heat calculation. The conventional mixed calorimetry method is easy to lose heat in the process of measuring the specific heat of frozen soil, and it is difficult to guarantee the accuracy of the specific heat; in addition, the latent heat The specific heat is superimposed into the test in a segmented form, and the unfrozen water content of the inverted permafrost generally has an error of 10% to 70%.

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