TEST RESEARCH ON MECHANISM OF FREEZING AND THAWING CYCLE RESULTING IN LOESS SLOPE SPALLING HAZARDS IN LUOCHUAN
YE Wanjun1，2，YANG Gengshe1，PENG Jianbing2，HUANG Qiangbing2，XU Yanfeng1
(1. School of Architecture and Civil Engineering，Xi'an University of Science and Technology，Xi'an，Shaanxi 710054，China；
2. Key Laboratory of Western Mineral Resources and Geological Engineering of Ministry of Education，Chang?an University，
Xi'an，Shaanxi 710054，China)
Abstract：The freezing and thawing cycle results in spalling hazards in loess slope in Luochuan. For comparison，the samples of loess suffering from spalling hazards in Luochuan and those not spalling have been collected respectively. In order to simulate the freezing and thawing process of the natural loess slopes，the test on the freezing and thawing cycle is carried out in the open conditions without any water being replenished，which is to observe the change of the properties of soil samples on the surface as well as its height，dry density，water content，cohesion and internal frictional angle under the function of freezing and thawing cycle. The test results indicate that in the first few cycles，the samples collected from Luochuan have slight increase in volume and water content. The soil structure is destroyed by the icy freezing expansive force in the process，which cannot be recovered in the thawing process. The soil strength is weakened by repeated freezing and thawing processes. After about ten cycles of freezing and thawing，the physico-mechanical condition of soil tends to be stable. While in the thawing process，the interface of water and ice has the softening function of water and the facilitating effect. If there is very good exposed surface，the spalling hazards in loess slopes may easily occur along this interface between water and ice；the negative pore water pressure may occur at the frozen edge in the process of freezing of soil samples. The soil density increases，while the volume decreases，and the soil strength is enhanced；in the process of thawing，the effective stress reduces；the total stress remains unchanged；the thawing volume is larger than the frost heaving amount. The cohesion of soil is slightly enhanced；therefore，it is not likely to have spalling hazards.
叶万军1，2，杨更社1，彭建兵2，黄强兵2，徐延峰1. 冻融循环导致洛川黄土边坡剥落病害产生机制的试验研究[J]. 岩石力学与工程学报, 2012, 31(1): 199-205.
YE Wanjun1，2，YANG Gengshe1，PENG Jianbing2，HUANG Qiangbing2，XU Yanfeng1. TEST RESEARCH ON MECHANISM OF FREEZING AND THAWING CYCLE RESULTING IN LOESS SLOPE SPALLING HAZARDS IN LUOCHUAN. , 2012, 31(1): 199-205.
荚 颖. 辽西风积土特性及冻融后结构性演变试验研究[硕士学位论文][D]. 辽宁：辽宁工程技术大学，2006.(LAI Ying. Test study of the characteristic of Liaoxi Aeolian soil and its structural change after freezing and thawing[M. S. Theses][D]. Liaoning：Liaoning Technical University，2006.(in Chinese))
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2012, Vol. 31 
