A critical review on the developments of rock support systems in high stress ground conditions

Ghorbani, M.; Shahriar, K.; Sharifzadeh, Mostafa; Masoudi, Reza

doi:10.1016/j.ijmst.2020.06.002

“…After the construction of a section of RBB was completed, a row of 17.8 mm diameter by 8200 mm long cables spaced 800 mm apart were installed at the roof 200 mm from the RBB [42]. These cables had a deviation angle of 12°to the goaf side.…”

Section: Rbb Determination and Reinforcementmentioning

confidence: 99%

Theory and Application of Gob-Side Entry Retaining in Thick Three-Soft Coal Seam

Jun-chao

¹

,

Zhang²

2021

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With the characteristic of less roadway excavation and high resource recovery, gob-side entry retaining (GER) technology is a safe and efficient green mining technology. Many experts and scholars have done extensive research on its principle and application. However, GERs are rarely used in thick soft coal seams. In this paper, based on the geological conditions of a coal mine in China, we propose a novelty approach of GER in thick three-soft coal seam (it means a single seam with a soft roof and a soft floor). The engineering scheme includes roadway expansion, large section roadway support, cutting roof to relieve pressure, and road-inside backfill body construction. The established mechanical and numerical calculation models effectively guide the engineering practice. Field observations showed that all the processes met the requirements of field production. The research results could provide theoretical guidance for the application of GER under similar geological conditions.

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“…The preparation of FPTSS consists of the owing steps: (1) xing the hollow PVC tube on the water-proof wooden base (Figure 4a); (2) lling the xed hollow PVC tube with coal rejects (Figure 4b); (3) mixing the CMT grout material with requested water and then dumping the mixed slurry into the lumped coal rejects (Figure 4c); ( 4) cutting E-glass bre sheet with requested length (Figure 4d); and (5) embedding the bre sheet into the epoxy resin to generate the FRP composite and then wrapping the FRP jacket on the surface of the PVC tube (Figure 4e). Note that only steps (1)-( 3) are requested for preparation of LFB specimens, FTSS specimens and PTSS specimens.…”

Section: Preparation Of Specimensmentioning

confidence: 99%

“…Maintaining the integrity of rock surface for underground roadway is always the main concern for strata controlling engineers, the di culty of which generally increases with the depletion of shallow coal resources [1][2][3]. It has been well noted either from the practice application or the theoretical foundation that conventional primary support techniques (e.g., rock bolt and cable bolt) cannot successfully prevent the serve deformation of surrounding rock for these roadways subjected to the complex geological conditions.…”

Section: Introductionmentioning

confidence: 99%

An Innovative Tubular Standing Support Incorporating PVC and FRP Composites: Laboratory Tests

Zhao

¹

2021

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With the depletion of shallow resources, the drawbacks of conventional bolting system in sustaining the integrity of the roadway have drawn much attention. Developing the innovative secondary standing support is therefore to be urgent. This paper presents a hybrid tubular standing support, which consists of an exterior container made of PVC and bre-reinforced polymer (FRP) composites and the in ll material made of coal rejects and high owable cementitious grout material. Compared with other marketable standing support, the combination application of the large rupture strain PVC tube and the FRP composite with high strength-to-weight ratio can provide the effective con nement to in ll material, which may result in the strain hardening behaviour. The use of coal reject to generate the back ll material is believed to be effective and thus is attractive from the design aspect. To verify these mentioned advantages, a series of compression tests were conducted on this FRP-PVC tubular standing support (FPTSS) with different thickness of the FRP jacket. In addition, the compression tests were also conducted to investigate the compressive behaviour of FRP tubular standing support (FTSS) and PVC tubular standing support (PTSS). Test results indicated that the combination of FRP and PVC composite achieve the superior behaviour either in terms of the compressive strength or the deformation ability.

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“…However, the surrounding rock loosening pressure is the pressure directly acting on the supporting structure by the gravity of loosened or collapsed rock mass. e quantity, property, and distribution law of surrounding rock loosening pressure play an important role in the design, construction, and operation of the supporting system [1][2][3][4][5][6][7]. If tunnel is not supported timely after excavation, there will be a transfixion sliding surface in surrounding rock.…”

Section: Introductionmentioning

confidence: 99%

Calculation Model and Influencing Factors of Surrounding Rock Loosening Pressure for Tunnel in Fold Zone

Liu

¹

,

Xie

²

,

Rao

³

2021

Advances in Civil Engineering

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This research aims to study the surrounding rock loosening pressure variation law of tunnel in the fold area. Based on the calculation method of surrounding rock loosening pressure for shallow tunnel, a new calculation model of the surrounding rock pressure was proposed for tunnel in the fold area; through this calculation model, the effects of tectonic stress (F), the angle ( φ 1 ) between tectonic stress and horizontal plane, tunnel buried depth (h), friction angle ( θ ), the multiple (k) between tectonic stress and rock mass gravity in the upper part of the tunnel, lateral pressure coefficient ( λ ), and tunnel midline offset (t) on tunnel surrounding rock loosening pressure in fold area are studied, respectively. Results show that in the anticline area, when φ 1 increases, the vertical loosening pressure (q) decreases; when q > 0, the surrounding rock is in the elastic deformation stage, and q decreases monotonously as F increases; when q < 0, the rock mass is in the initial stage of failure, and as F continues to increase, the number of internal cracks increases, the rock mass reaches its ultimate bearing capacity and then fails completely, and q increases linearly in this process; q decreases with the increase of θ and k; the greater k is, the easier it is to reach its bearing limit; the horizontal loosening pressure (e) increased monotonously with the increase of h and λ . The research process of surrounding rock loosening pressure of tunnel in the syncline area is similar to that of tunnel in the anticline area; q decreases with the increase of θ and λ ; q monotonically increases with F increasing.

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A critical review on the developments of rock support systems in high stress ground conditions

Cited by 90 publications

References 29 publications

Theory and Application of Gob-Side Entry Retaining in Thick Three-Soft Coal Seam

Theory and Application of Gob-Side Entry Retaining in Thick Three-Soft Coal Seam

An Innovative Tubular Standing Support Incorporating PVC and FRP Composites: Laboratory Tests

Calculation Model and Influencing Factors of Surrounding Rock Loosening Pressure for Tunnel in Fold Zone

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