Abstract

Characterized by low bearing capacity and high compressibility, warm and ice-rich frozen soil is a kind of problematic soil, which makes the original frozen ground formed by of that unreliable to meet the stability requirements of engineering infrastructures and foundations in permafrost regions. With the design and construction of major projects along the Qinghai-Tibet Engineering Corridor (QTEC), such as expressway and airport runway, it is a great challenge to favor the stability of overlying structures by formulating the proper engineering design principles and developing the valid engineering supporting techniques. The investigations carried out in recent years indicated that warm and ice-rich permafrost foundations were widespread, climate warming was significant, and the stability of existing engineering structures was poor, along the QTEC. When the warm and ice-rich frozen ground is used as the foundation soil, the implementation of ground improvement is an alternative measure to enhance the bearing capacity of foundation soil and eliminate the settlement of structures during operation, in order to guarantee the long-term stability of the structures. Based on the key factors determining the physicomechanical properties of frozen soil, an innovative idea of stabilizing the warm and ice-rich frozen soil based on chemical stabilization is proposed in this study, and then, an in situ ground improvement technique is introduced. This study intends to explore the feasibility of ground improvement in warm and ice-rich permafrost regions along the QTEC based on in situ chemical stabilization and provide the technical support and scientific reference to prevent and mitigate the hazards in the construction of major projects in the future.

Highlights

  • Introduction e QinghaiTibet Engineering Corridor (QTEC) runs from Golmud to Lhasa, traversing 550 km of permafrost regions in the interior of the Qinghai-Tibet Plateau (QTP) in northsouth direction [1]

  • Permafrost on the QTP is thin, thermally unstable, and sensitive to climate change [5,6,7], and the warm and ice-rich frozen soil is widely distributed [8, 9]. e physicomechanical properties of the warm and ice-rich frozen soil feature high unfrozen water content [10], low shear strength [11, 12], and high compressibility [13, 14], leading to the fact that the foundation soil with the warm and ice-rich frozen soil is low in bearing capacity and large in settlement

  • The existing linear projects, such as the Qinghai-Tibet Highway (QTH), the Qinghai-Tibet Railway (QTR), the Golmud-Lhasa oil product pipeline, and the optical cable from Lanzhou to Lhasa, are all located in the Qinghai-Tibet Engineering Corridor (QTEC) within a width of less than 10 km [9, 15]

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Summary

Review Article

Honglei Wang ,1,2 Hu Zhang ,1 Mingtang Chai, Jianming Zhang, Zhizhong Sun, and Guoyu Li 1,4. Is study intends to explore the feasibility of ground improvement in warm and ice-rich permafrost regions along the QTEC based on in situ chemical stabilization and provide the technical support and scientific reference to prevent and mitigate the hazards in the construction of major projects in the future. By reviewing the current situation of frozen ground conditions for engineering geology, climate changes, and existing engineering structural stability along the QTEC, this study explains the necessity of ground improvement in warm and ice-rich permafrost regions affected by climate warming and anthropogenic activities. A better understanding of the frozen ground conditions for engineering geology along the QTEC provides the scientific guideline for construction site selection, engineering design principle, construction technology, operation maintenance, and freezing-thawing hazard prevention to major projects in permafrost regions [9].

National Meteorological Station
Icy soil
Active layer Dry jet mixing pile
Findings
Summary
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