Dynamic Mechanical Properties and Energy Dissipation Characteristics of Frozen Soil Under Passive Confined Pressure
- PDF / 5,326,405 Bytes
- 20 Pages / 595.276 x 790.866 pts Page_size
- 70 Downloads / 196 Views
ISSN 1860-2134
Dynamic Mechanical Properties and Energy Dissipation Characteristics of Frozen Soil Under Passive Confined Pressure Jinxuan Jia1
Huaiping Tang1
Huijian Chen1
1
( Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China)
Received 29 June 2020; revision received 17 October 2020; Accepted 20 October 2020 c The Chinese Society of Theoretical and Applied Mechanics 2020
ABSTRACT Impact compression tests on frozen soil samples with different freezing temperatures and subjected to passive confined pressure were performed using a split Hopkinson pressure bar at different loading strain rates. The three-dimensional stress–strain curves of the frozen soil samples under the corresponding conditions were obtained. The experimental results showed that, when the frozen soil was loaded to its elastic limit, shear failure occurred, the bearing capacity of pore ice was lost, and the thawed soil functioned as the main stress-bearing body. Nevertheless, the capacity of frozen soil to withstand hydrostatic pressure continued to increase. The dynamic mechanical properties of the frozen soil under passive confined pressure were observed to be strongly related to the loading strain rate and freezing temperature. As the loading strain rate increased, the secant modulus, elastic modulus, and strength (including the shear strength) of the frozen soil increased, whereas its Poisson’s ratio and coefficient of lateral pressure decreased. As the freezing temperature decreased, the secant modulus, elastic modulus, and shear strength of the frozen soil increased; however, its Poisson’s ratio and coefficient of lateral pressure decreased. When the frozen soil was subjected to impact loading under passive confined pressure, energy dissipation occurred due to plastic deformation, mesoscopic damage evolution, and ice–water phase transition. When shear failure occurred, the absorption energy per unit volume of frozen soil increased as the freezing temperature decreased and the loading strain rate increased.
KEY WORDS Frozen soil, Split Hopkinson pressure bar, Passive confined pressure, Dynamic mechanical properties, Energy dissipation
1. Introduction Frozen soil is a heterogeneous and anisotropic four-phase complex material composed of solid mineral particles, viscoplastic ice inclusions, liquid water, and gaseous inclusions [1]. Frozen soil is ubiquitous in nature [2]. In recent years, the construction of infrastructures in cold regions (such as the China–Pakistan Economic Corridor and the Beijing–Moscow High Speed Railway), as supported by the Belt and Road Initiative, has rapidly increased. Furthermore, tremendous growth in the comprehensive utilization of energy in the Arctic has also been observed. Consequently, artificial ground freezing methods have been widely used in underground engineering construction, including mine construction, foundation pit support, and tunnel engineering. In certain cases, the rock and soil in nat
Data Loading...
