Abstract
Shaft lining in ultradeep mines on the coast of eastern China under the complex external environments of “high in situ stress and high osmotic pressure” has the disadvantages of failure; to solve this problem, the field test of high-performance concrete shaft lining structure was carried out in Sha-ling gold mine. The field test study of the high-performance concrete shaft lining was carried out in a −1120 m ingate and a −1114 m to −1124 m shaft. Its stress and deformation were monitored and analyzed. The maximum compressive stress of the HPC shaft lining structure at the level of −1117.7 m of the air intake shaft is 1.91 MPa. Based on the Von-Mises yield theory and the analytical solution of thick-walled cylinder theory, the ultimate limit of the high-performance concrete shaft lining in the Sha-ling gold mine was obtained. The high-performance concrete shaft lining strain changes smoothly, and concrete strain can be divided into three stages: the rapid growth period, the slow growth period, and the stable period. The monitoring results show that the high-performance concrete shaft lining has excellent mechanical properties in the external environment of high in situ stress, which can be used as a reference for the support design of similar projects.
Highlights
Under the complex external environments of “high in situ stress, high ground temperature, high water pressure, and strong excavation disturbance” [1], the physical and mechanical properties of deep rock masses are generally different from those of shallow rock masses [2, 3]; the rock masses change from an elastic state to a plastic state. e pressure distribution of the surrounding rock and the excavation disturbance stress path will affect the stability of the surrounding rock
Stress Characteristics and Analysis of the high-performance concrete (HPC) Shaft Lining at −1117.7 m Level. e shaft lining stress variation of the HPC at the −1117.7 m level is shown in Figure 7. e tensile stress of the shaft lining is positive, and the compressive stress is negative
Combined with the distribution of in situ stress and the change law of surrounding rock, the stress change characteristics of the shaft lining are analyzed. e conclusions are drawn: (1) e maximum compressive stress of the HPC shaft lining structure at the level of −1117.7 m of the air intake shaft in the Sha-ling gold mine is 1.91 MPa, and the compressive stress of the high-performance concrete shaft lining will not reach its limit stress. e HPC shaft lining can meet the complex supporting of the metal mine depth shaft in a coastal area
Summary
Under the complex external environments of “high in situ stress, high ground temperature, high water pressure, and strong excavation disturbance” [1], the physical and mechanical properties of deep rock masses are generally different from those of shallow rock masses [2, 3]; the rock masses change from an elastic state to a plastic state. e pressure distribution of the surrounding rock and the excavation disturbance stress path will affect the stability of the surrounding rock. Under the complex external environments of “high in situ stress, high ground temperature, high water pressure, and strong excavation disturbance” [1], the physical and mechanical properties of deep rock masses are generally different from those of shallow rock masses [2, 3]; the rock masses change from an elastic state to a plastic state. E pressure distribution of the surrounding rock and the excavation disturbance stress path will affect the stability of the surrounding rock. In the process of shaft excavation, water inrush, rock-burst, lamping, and other engineering support problems are frequent occurrences. Some high-grade shaft lining concrete may even suffer brittle failure in the deep external environment of high in situ stress and high osmotic pressure. The deep strata and deep-water quality in the coastal area are rich in Cl− and SO24− ions, putting the shaft lining concrete at risk of chemical corrosion [7,8,9], which seriously affects the strength and durability of the concrete [10,11,12,13] and dramatically shortens the life of the shaft lining
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