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Experiment of freeze-thaw cycling effect on silty clay under different environmental freezing temperatures(PDF)

《长安大学学报》自然版[ISSN:1006-6977/CN:61-1281/TN]

Issue:
2017年04期
Page:
41-49
Research Field:
冻土路基专栏
Publishing date:

Info

Title:
Experiment of freeze-thaw cycling effect on silty clay under different environmental freezing temperatures
Author(s):
HU Tian-fei LIU Jian-kun LIU Da-wei
School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
Keywords:
engineering permafrost freeze-thaw cycling freezing temperature failure strength shear strength freezing contraction
PACS:
U416.168
DOI:
-
Abstract:
In order to study the influence of freezing temperature on freeze-thaw cycling of soil, a set of triaxial tests were conducted under different confining pressures (50, 100, 150 kPa) for samples based on silty clay from Qinghai-Tibet Plateau regarding different freeze-thaw cycle numbers (0, 1, 3, 6, 9, 12, 15 times) under different freezing temperatures (-5 ℃, -10 ℃, -15 ℃, -20 ℃, -25 ℃, -30 ℃). The results show that the level of freezing temperature considerably affects the soil freeze-thaw cycling. The failure strength decreases when freezing temperature changes from -5 ℃ to -15 ℃, and increases when freezing temperature changes from -15 ℃ to -30 ℃. Though volume of the surface increases under frozen condition, expansion and contraction coexist in freezing process. With the decrease of freezing temperature, it is earlier for expansion to reach the limit than contraction. Meanwhile, with the increase of freeze-thaw cycle number, the failure strength decreases dramatically, and then keeps constant. The failure strength achieves the relative stability index with less cycling times, when freezing temperature is lower. The migration rate inside samples becomes less when freezing temperature is lower, thus the amount of water migration correspondingly becomes less. Apparent shear strength parameters vary in the same regularity as failure strength, internal friction angle suffers a more significant effect on the freezing temperature than cohesion.

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Last Update: 2017-07-17