Abstract
To address the support problem of large-diameter drilling shafts in the west area of Zhangji coal mine, a thinner shaft lining structure composed of double layers of steel plate and high-performance concrete is proposed herein. Firstly, a series of tests of high-performance concrete preparation were carried out, and the optimized mix ratio of pumping concrete with 60–70 MPa strength for shaft lining of the drilled shaft was obtained. Then, shaft lining models were designed according to the similarity theory, and the mechanical properties of the shaft lining were experimentally studied by loading test. The test results showed that the stress state of concrete in the shaft was obviously improved, and the compressive strength of concrete was increased by 1.97–2.52 times. Finally, the results of the study were applied to a shaft in the control strata of the inlet shaft in the west area of Zhangji coal mine, which made it possible to use the drilling method to construct the shaft. The following field measurement showed that the annular strain of the shaft lining concrete was −487 με, which is far less than the ultimate strain value of C65 concrete, and the shaft lining structure was kept safe and reliable.
Highlights
The shaft drilling method, a modern mechanical shaft sinking method, is one of the most effective methods for sinking shafts through deep alluvium in coal mines
To provide a basis for engineering design and construction, in this paper we present a model test study on a high-performance shaft lining structure of this type and a field measurement analysis of its engineering application
Large amounts of strain data were obtained from the shaft lining model loading test and were
Summary
The shaft drilling method, a modern mechanical shaft sinking method, is one of the most effective methods for sinking shafts through deep alluvium in coal mines. The gap between the lining and the surrounding rock is filled with cement to constrain the shaft This method, characterized primarily by excellent safety (all the construction personnel are on the ground) and reliable quality of the poured concrete shaft lining, allows for the mechanized construction of vertical shafts in coal mines [1,2,3] and is suitable for use in the construction of new air shafts in operating coal mines. According to safety reconstruction requirements, an intake shaft and a return air shaft were to be constructed in the west zone of this coal mine They were designed to have net diameters of 8.3 and 7.2 m, drilling diameters of 10.8 and 9.6 m, and depths of 458.0 and 440.0 m, respectively. Each of the two shafts needed to pass through 401.2 m thick alluvial strata
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