Model Test Study on Natural Thawing Temperature Field of Artificial Ground Frozen Wall

Abstract

In order to visualize the evolution and distribution law of the ground temperature field during artificial freezing construction, an indoor model test study was carried out based on the independently constructed hygrothermal coupling artificial ground freezing test platform. The test results show that the soil temperature in the freezing process went through the three stages of a steep drop, a slow drop, and stabilization, the earliest closure position of the frozen wall was the intermediate point between two freezing pipes, and the thickness of the frozen wall on different sections showed Section 1 > Section 2 > Section 3 after 61 min of positive freezing. The soil temperature in the natural thawing process went through the four stages of a rapid rise, short hysteresis, a second rapid rise, and a linear slow rise. By fitting the test data, the distribution function of the pipe wall temperature along the pipe length under natural thawing conditions was obtained. The research results can provide a valid basis for the numerical calculation model of a three-dimensional non-uniform natural thawing temperature field and can also provide a reference for the design of settlement grouting under natural thawing conditions.

Calculation Method of the Design Thickness of a Frozen Wall with Its Inner Edge Radially Incompletely Unloaded

“…0.6 0.7 0.8 0.9 1.0 1. 1 Figure 6 shows that 𝑡 ̃ decreases significantly with 𝜎 . The larger α is, the slower 𝑡 ̃ decreases with 𝜎 .…”

“…0.6 0.7 0.8 0.9 1.0 1. 1 To facilitate the analysis of the influences of mechanical parameters, σc, E II , E III , k, and t are made dimensionless, as shown in Equation ( 43):…”

“…The technology for freezing shaft sinking is a special construction technology that utilizes artificial ground freezing methods to form a closed frozen geotechnical curtain (frozen wall) around a supporting structure (a shaft) by temporarily freezing the water in strata to improve the bearing capacity and water-sealing performance of the strata and protect the construction safety of shafts [1][2][3]. It has been gradually popularized and applied due to its outstanding advantages of strong adaptability, high reliability, and good technical and social benefits, and it has become the main construction technology for underground structures in deep water-bearing unstable soil layers and water-rich rock strata [4][5][6][7].…”