A Concrete-Filled Steel Tubular Yieldable Support for a Tunnel within Deep Soft Rock

Xu, Chang; Luo, Xulin; Liu, Guosheng

doi:10.1061/(asce)gm.1943-5622.0002423

Cited by 4 publications

(1 citation statement)

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“…New methods such as concrete lled steel tube, integrated support of shed cable, anchor cable with constant resistance and large deformation, combined grouting, and prestressed steel rod have been explored. Recently, new control methods such as portal support, full-section anchor cable, and ultra-high strength anchor bolt have appeared [15][16][17]. He [18] established the process function of mudstone's water absorption based on the water absorption tests of different mudstone samples, and analyzed the in uence rule of mudstone porosity size, mineral content and type, and occurrence of clay minerals on water absorption characteristics.…”

Section: Introductionmentioning

confidence: 99%

Study on Instability Mechanism of Soft Rock Roadway and Pressure-relief Bolt-grouting Support Technology

Yang,

Liu,

Luo

et al. 2023

Preprint

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Aiming at the engineering problem of roadway deformation and instability of expansive soft rock widely existed in Kailuan mining area, the mineral composition and microstructure of such soft rock were obtained by conducting scanning electron microscopy, X-ray diffraction experiments, uniaxial and conventional triaxial tests, etc., and the law of softening and expanding of such soft rock and the failure mechanism of surrounding rock were identified. The combined support scheme of multi-level anchor bolt, bottom corner pressure relief and fractional grouting is proposed. The tunnel supporting parameters are adjusted and optimized by FLAC3D numerical simulation, and three supporting methods of multi-layer anchor bolt, bottom corner pressure relief and fractional grouting are determined and their parameters are optimized. The study results show that: 1) The total amount of clay minerals is 53%~75%, and pores, fissures, nanoscale and micron layer gaps are developed, providing a penetrating channel for water infiltration to soften the surrounding rock； 2) The three-level anchor pressure-relief and grouting support technology can control the sinking amount of the roof within 170mm, the bottom drum amount within 210mm, the bolts of each level is evenly distributed in tension, and the maximum stress and bottom drum displacement in the pressure relief area are significantly reduced; 3) The pressure-relief groove promotes the development of bottom corner cracks, accelerates the secondary distribution of peripheral stress, and weakens the effect of high stress on the shallow area. Using time or displacement as the index, optimizing the grouting time, filling the primary and excavation cracks, blocking the expansion and softening effect of water on the rock mass, realizing the dynamic unity of structural yielding pressure and surrounding rock modification, has guiding significance for the support control of soft rock roadway.

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Section: Introductionmentioning

confidence: 99%