The Experimental Study On The Influence Of Temperature On The Coefficient Of Lateral Earth Pressure At Rest For Frozen Soils

The coefficient of lateral earth pressure at rest?K₀?of soil is a very important parameter in soil mechanics,and K₀ has been widely used in engineering and soil mechanics constitutive theories.With the development of China's national strategy,more and more projects need to face the problem of frozen soil.However,the experimental and theoretical research on K₀ of frozen soils is yet to be carried out,far from meeting the needs of engineering activities.In this paper,the existing methods for the determination of K0 were summarized,Then the author designed an experiment apparatus and measured K0 coefficient of three kinds of frozen soil.The main results are as follows:?1?The frozen soil is greatly affected by temperature and has a large compression modulus.Therefore,in light of the testing experience for mearing K₀ of unfrozen soils and considering the characteristics of frozen soils,the author developed an apparatus for measuring K0 for frozen soils.After that,the author completed apparatus calibration and functional test.This apparatus adopts the sample container with rigid side double layered walls with a strain gauge in between through which the lateral stress can be obtained.By an applied vertical stress and the corresponding the lateral stress in the frozen soil sample,their ratio,K0 is calculated.Through thermalstat circulation and secondary temperature control device,improve the accuracy of temperature control to±0.1?,which is suitable for measuring K0 of warm frozen soils.The apparatus is then verified with respect to the testing results.Therefore,accuracy of both temperature and stress are guaranteed so as to ensure the test accuracy of K₀ of frozen soils.This work provides a practical and feasible measurement method for measurement of K0 of frozen soils.?2?In this paper,three materials including the Chinese ISO standard sand,a silty sand and a clay secured from the Qinghai-tibetan plateau are used to investigate the influence of temperature on the K0 of different frozen soils through the laterally confined compression experiment under different temperatures.On this basis,aiming at the determination of K0 for frozen soils,the author designs a set of experiment methods which can provide frozen soil K0coefficient for practical engineering.?3?It is found through the testing program that the temperature of frozen soil has an important impact on K0,and K0 of frozen soils changes along with temperature in certain principles.i.e.,for the temperature between-1?to-2?,the temperature is rather dominant,under low temperatures,K₀ does not change considerably.At the same time the author also found that temperature influences K₀ of the three kinds of soil differently.The results of this paper provide reference instruments and research methods for the peer,provide the applied value of K₀ coefficient experiment technology and scheme for the engineering department,and preliminary discussion on the influence factors of the K0coefficient of frozen soil.