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))
Your browse does not support frame! " target="_blank">
[9]
王铁行,罗少锋,刘小军. 考虑含水率影响的非饱和原状黄土冻融强度试验研究[J]. 岩土力学,2010,31(8):2 378-2 382.(WANG Tiehang,LUO Shaofeng,LIU Xiaojun. Testing study of freezing- thawing strength of unsaturated undisturbed loess considering influence of moisture content[J]. Rock and Soil Mechanics,2010,31(8):2 378-2 382.(in Chinese))
Your browse does not support frame! " target="_blank">
[10]
连江波,张爱军,郭敏霞,等. 反复冻融循环对黄土孔隙比及渗透性的影响[J]. 人民长江,2010,41(12):56-62.(LIAN Jiangbo,ZHANG Aijun,GUO Minxia,et al. Influence of iterative freezing- thawing on void ratio and permeability of loess[J]. Yangtze River,2010,41(12):56-62.(in Chinese))
Your browse does not support frame! " target="_blank">
[12]
齐吉琳,马 巍. 冻融作用对超固结土强度的影响[J]. 岩土工程学报,2006,28(12):2 082-2 086.(QI Jilin,MA Wei. Influence of freezing-thawing on strength of over consolidated soils[J]. Chinese Journal of Geotechnical Engineering,2006,28(12):2 082-2 086. (in Chinese))
Your browse does not support frame! " target="_blank">
[4]
齐吉琳,张建明,朱元林. 冻融作用对土结构性影响的土力学意义[J]. 岩石力学与工程学报,2003,10(2):2-4.(QI Jilin,ZHANG Jianming,ZHU Yuanlin. Influence of freezing-thawing on soil structure and its soil mechanics significance[J]. Chinese Journal of Rock Mechanics and Engineering,2003,10(2):2-4.(in Chinese))
Your browse does not support frame! " target="_blank">
[7]
毕贵权,张 侠,李国玉,等. 冻融循环对黄土物理力学性质影响的试验[J]. 兰州理工大学学报,2010,36(2):114-117.(BI Guiquan,ZHANG Xia,LI Guoyu,et al. Experiment of impact of freezing- thawing cycle on physico-mechanical properties of loess[J]. Journal of Lanzhou University of Technology,2010,36(2):114-117. (in Chinese))
Your browse does not support frame! " target="_blank">
[11]
中华人民共和国国家标准编写组. GB/T 50123—1999 土工试验方法[S]. 北京:中国计划出版社,1999.(The National Standards Compilation Group of People?s Republic of China. GB/T 50123—1999 Standard for soil test method[S]. Beijing:China Planning Press,1999.(in Chinese))
Your browse does not support frame! " target="_blank">
[8]
宋春霞,齐吉琳,刘奉银. 冻融作用对兰州黄土力学性质的影响[J]. 岩土力学,2008,29(4):1 078-1 080.(SONG Chunxia,QI Jilin,LIU Fengyin. Influence of freeze-thaw on mechanical properties of Lanzhou loess[J]. Rock and Soil Mechanics,2008,29(4):1 078-1 080.(in Chinese))
Your browse does not support frame! " target="_blank">
[2]
齐吉琳,程国栋,VERMEER P A. 冻融作用对土工程性质影响的研究现状[J]. 地球科学进展,2005,20(8):887-893.(QI Jilin,CHENG Guodong,VERMEER P A. State-of-the-art of influence of freeze-thaw on engineering properties of soils[J]. Advances in Earth Sciences,2005,20(8):887-893.(in Chinese))
[6]
董晓宏,张爱军,连江波,等. 非饱和冻融黄土固结蠕变特性研究[J]. 人民长江,2010,41(3):88-91.(DONG Xiaohong,ZHANG Aijun,LIAN Jiangbo,et al. Study on consolidation creep behavior of unsaturated loess suffering freezing-thawing cycles[J]. Yangtze River,2010,41(3):88-91.(in Chinese))
Your browse does not support frame! " target="_blank">
[1]
董瑞琨,许兆义,杨成永. 青藏高原冻融侵蚀动力特征研究[J]. 水土保持学报,2000,14(4):12-16.(DONG Ruikun,XU Zhaoyi,YANG Chengyong. Dynamic and characteristic of freezing-thawing erosion on Qinghai—Tibet plateau[J]. Journal of Soil Water Conservation,2000,14(4):12-16.(in Chinese))
Your browse does not support frame! " target="_blank">
[5]
李国玉,马 巍,李 宁,等. 冻融对压实黄土工程地质特性影响的试验研究[J]. 水利与建筑工程学报,2010,8(4):5-7.(LI Guoyu,MA Wei,LI Ning,et al. Experimental research on impact of freezing and thawing on geotechnical properties of compacted loess[J]. Journal of Water Resources and Architectural Engineering,2010,8(4):5-7.(in Chinese))
Your browse does not support frame! " target="_blank">