CT Scan on Frozen Roadbed Soil under Dynamic Triaxial Test Condition of Beilu River Section, Qinghai-Tibet Railway of China

by Lixia Wang, Jilin Institute of Architecture and Civil Engineering, P.O. Box 130021, City, Changchun, P.R. China, wanglixiaql@163.com,
Xianzhang Ling, Institute of Subgrade and Protection Engineering, Harbin Institute of Technology, P.O. Box 150090, City, Harbin, P.R. China, Xianzhang_ling@263.net,
Feng Zhang, Institute of Subgrade and Protection Engineering, Harbin Institute of Technology, P.O. Box 150090, City, Harbin, P.R. China,
Yibin Pu, State Key Laboratory of Frozen Soil Engineering, CAS, P.O. Box 150090, City, Lanzhou, P.R. China, wanglixiaql@163.com,
Liquan Wu, School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, P.O. Box 310023, City, Hangzhou, P.R. China, wuliquanl966@163.com,

Document Type: Proceeding Paper

Abstract: As an effective scanning method with no damage, the CT scanning technique is used more widely in studying the dynamic deformation of frozen soil. Aiming at stability and dynamic deformation of frozen soil, the structural change before and after a dynamic tri-axial test, failure type and their main affecting factors of frozen soil taken from roadbed of Qinghai-Tibet Railway are discussed from microstructure according to CT scanning results. It indicates that water content, temperature and confining pressure are the main affecting factors. Change of density, strength and modulus during dynamical deformation decreases with an increase of water content and confining pressure, similarly the changes of the microstructure and structure. When temperature decreases, density, strength and modulus decrease rapidly, but the microstructure and structural changes decreases. When axial dynamic strength decreases, degradation of density, strength, modulus changes from large to small at the beginning and then from small to large, but structure change and demagnification are the reverse of that. The dynamic failure type of the frozen soil depends on the composite in condition of higher water content and lower temperature, but belongs to loose expand and border cracking when water content is lower, belongs to equally expand type when confining pressure or temperature is higher, belongs to composite and uniform expand type when confining pressure is lower and water content is higher, and belongs to loose failure type when confining pressure is higher and water content is lower. To frozen soil, these CT scanning results and recognition not only benefit the study pf stability and dynamic deformation, but also provide important data for further dynamic characteristics studies and establishing dynamic deformation models.

Subject Headings: Soil dynamics | Frozen soils | Dynamic tests | Triaxial tests | Imaging techniques | Soil deformation | Water content | Water pressure | Soil properties | Highway and road conditions | Soil tests | Temperature effects | Structural dynamics | North America | Connecticut | United States | China | Asia

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