﻿ 人工冻结施工便道力学性能试验研究

# 人工冻结施工便道力学性能试验研究Experimental Research on Mechanical Property of Artificial Freezing Construction Road

Abstract: At present, the artificial freezing method is widely used to temporarily reinforce the strength of the soil so that the soil layer strength is greatly increased during the freezing period to meet the engineering needs. After melting, it can be restored to its original condition, reducing pollution and damage to the environment. In order to explore the application prospect of artificial freez-ing method in construction access road of transmission line, the physical mechanics perfor-mance tests of the ice and frozen soil have been developed. And the model experiment has been carried on to study the mechanical property of the artificial freeze roadbed. The results of the experiment show that: as the temperature decreases, the uniaxial compressive strength of ice specimen increases gradually, and the cohesive strength and internal friction angle of frozen soil have the tendency which increases; the compressibility of backfill soil in frozen state is signifi-cantly lower than that at normal temperature; and under the same load, the overall displace-ment of the frozen road decreases with the increase of the artificial water flooding freeze pavement thickness, and small construction machines can pass through pavements with a thickness more than 10 cm.

1. 引言

2. 试验概况

2.1. 冰和冻土试样试验

Table 1. Specimen size and quantity

2.2. 人工冻结模型试验

Table 2. Model experiment conditions

3. 试验结果和分析

3.1. 冰试样单轴抗压强度

Table 3. Test results of uniaxial compressive strength experiment

(a) (b) (c)

Figure 1. Curves: stress-strain result of uniaxial compressive strength experiment. (a) Curves: stress-strain result of uniaxial compressive strength experiment at −5˚C; (b) Curves: stress-strain result of uniaxial compressive strength experiment at −10˚C; (c) Curves: stress-strain result of uniaxial compressive strength experiment at −15˚C

3.2. 冻土试样三轴剪切试验

${\sigma }_{1}=\frac{1+\mathrm{sin}\phi }{1-\mathrm{sin}\phi }{\sigma }_{3}+2c\frac{\mathrm{cos}\phi }{1-\mathrm{sin}\phi }$ (1)

Table 4. Triaxial shear test results of frozen soil

3.3. 人工注水冻结路面模型试验

Figure 2. Curves: load-displacement result of frozen roadbed model experiment

(a)(b)

Figure 3. Curves: load-displacement result of artificial water flooding freeze pavement experiment. (a) Ice thickness: 10 cm and 30 cm; (b) Ice thickness: 2 cm and 5 cm

4. 小结

1) 对于土体和冰试件，强度指标和温度有直接对应关系。随着温度的降低，强度有进一步提高的趋势。

2) 回填土的压缩性在低温冻结状态下显著降低，模型试验结果显示变形模量可提高20倍。

3) 在相同荷载作用下，人工注水冻结路面厚度越大，路面和路基的整体位移就越小，厚度大于10 cm的路面可以通过小型施工机械。

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