Chengguo Zhang

• UNSW Sydney

Longwall mining is a productive method for underground coal resource recovery, but usually leads to extensive fracture networks that facilitate groundwater drainage into mined-out areas. Accurately assessing the coverage and magnitude of induced groundwater depressurisation is crucial for sustainable mining practices, but is often constrained by si...

Catastrophic dynamic rock failure is one of the most challenging problems existing in the fields of civil tunneling and mining. It occurs in complex environments of geology, stress and excavation, and there is no one set of circumstances that is responsible for the phenomenon. However, a major contributing factor is believed to be energy storage an...

With the increasing complexity and broader scope of underground operations, groundwater is widely encountered during rock excavation. Groundwater has diverse pH levels and components, the hydro deterioration of rock is a significant factor that threatens sustainable mining. Environments with the presence of groundwater are prone to chemical corrosi...

Rockburst, a dynamic damage phenomenon occurring in high-stress rock mass conditions, poses a significant risk to the safety of deep underground engineering operations due to sudden and violent rock failure. Mitigating rockburst damage is a difficult challenge encountered during underground excavation. Ground support systems are extensively utilise...

Background Rock slope instability is a complex geotechnical issue that is affected by site-specific rock properties, geological structures, groundwater, and earthquake load conditions. Numerous studies acknowledge these aleatory uncertainties in slope stability assessment; however, understanding the rock behaviour could still be improved. Therefore...

To solve the problem of controlling the stability of small coal pillars under the mining disturbance of the adjacent working face, the fourth panel 403 and 404 working faces of the Gaojiabao coal mine with two mining roadways is taken as the object of this research. The comprehensive research method of combining mechanical theory analysis, coal dyn...

Accurately predicting the hydromechanical behaviour of rock fractures is challenging due to the significant influence of shear-induced fracture geometries. This work proposes an improved shear-flow model that accurately estimates nonlinear fluid flow behaviour as well as shear mechanical behaviour. To predict shear mechanical behaviour, the model e...

Rock quality designation (RQD), as a well-accepted and appliable rock quality index, is crucial in geotechnical engineering. Current RQD estimation mainly relies on either manual statistics or the image binarisation method, while the former approach surrenders high labour intensity and low efficiency and the latter one is constrained by image acqui...

The interaction of mining and the surface water or aquifer system in varying overburden strata conditions is one of the most critical aspects of sustainable mining practices, that can lead to water loss or water inrush into openings. This paper examined this phenomenon in a complex strata condition via a case study, and proposed a new mining design...

The rock mass around deep roadways has obvious creep characteristics in high-stress environments. Meanwhile, the cyclic impact load induced by roof fracturing also causes dynamic damage to the surrounding rock, leading to long-term large deformation. This paper examined the rock mass deformation mechanism around deep roadways based on the theory of...

Coal burst is one of the principal hazards in development panels of underground coal mines. This study develops a practical approach to quantitatively estimate coal burst proneness in development roadways. A rigorous numerical and statistical study is conducted to establish a novel burst proneness rating (BPR) system based on energy release charact...

Risk evaluation of roadway rockburst refers to quantitatively dividing the rockburst-prone area into multiple sections with different risk levels at the mining design stage, according to the geological and mining technical factors influencing the rockburst occurrence, for partitioned and graded management of rockburst. Based on this, a targeted roc...

Natural rock joint permeability deviates from the classic fluid flow governing equations due to the inherent fracture surface roughness (i.e., contact points, spatial correlation, matching, varying aperture, isolated voids, infilling material, tortuosity and channellings) and engineering disturbance such as excavations. To improve the accuracy of f...

Ground motions resulting from seismic waves are one of the main factors to trigger coal burst hazards in underground mines. Ground motion induced dynamic impacts may apply to the highly stressed coal/rock mass and initiate dynamic failure. Although ground motion analysis has been widely used in burst-prone hard rock mines for designing support syst...

Ground support is widely implemented to mitigate dynamic rock failures in underground mines. This paper investigated the ground support requirements in burst-prone mines to mitigate the catastrophic dynamic rock failures of rock and/or coal bursts. First, the ground support principles and considerations in burst-prone conditions are identified. The...

Geological structures such as faults and dykes are one of the main contributors of catastrophic rock and/or coal burst events in underground mines. This study focuses on the impacts of faults on burst proneness in development roadways using the Universal Distinct Element Code (UDEC). A sensitivity analysis on the influence of fault proximity to a r...

Ground support is widely implemented to mitigate dynamic rock failures in underground mines. This paper investigated the ground support requirements in burst-prone mines to mitigate the catastrophic dynamic rock failures of rock and/or coal bursts. First, the ground support principles and considerations in burst-prone conditions are identified. The...

Data integrity and reliability during seismic event detection are the main factors limiting the effectiveness of seismic monitoring systems in underground mines. As it is impossible for current seismic monitoring systems to record all mining-induced seismic events, the incomplete seismic dataset may cause significant bias during data analyses and i...

A rock and/or coal burst is an uncontrolled failure that releases a massive amount of kinetic energy, inducing excessive displacement of coal/rock mass. Combined support to controlling rock and/or coal dynamic failures is an essential part of the rock burst management. In the design of rock support, it is essential to consider not only the capacity...

The presence of geological faults is a significant contributing factor to coal burst in underground mining. In this study, a large-scale discontinuum model was established based on geological and geotechnical conditions in a mine site, where a longwall face passed through a major fault. Four model indicators were calculated during the longwall retr...

Coal bursts have emerged as the most critical mining hazard for underground coal mines around the world. Seismic monitoring and seismic clustering analysis are the cornerstones to develop an understanding of and to quantify coal burst hazards. The prerequisite to successfully detect seismic clustering behaviours is the accuracy of locating seismic...

Coal burst occurrences are affected by a range of mining and geological factors. Excessive slipping between the strata layers may release a considerable amount of strain energy, which can be destructive. A competent strata is also more vulnerable to riveting a large amount of strain energy. If the stored energy in the rigid roof reaches a certain l...

Underground coal mining is inherently hazardous, with uncontrolled ground failure regarded as one of only several critical risks for multiple fatality events. Development, implementation and management of overarching systems and procedures for maintaining strata control is an important step to mitigating the impact of ground failure hazards at a mi...

Mining-induced seismicity is one of the dynamic energy sources that can trigger coal burst. This paper presents a new methodology to assess coal burst risks under different loading conditions by examining seismic energy attenuation and fracture size. Two new indices are proposed: (1) Dynamic Load Index (DLI) quantifies the magnitude of dynamic load...

The dynamic capacity of a support system is dependent on the connectivity and compatibility of its reinforcement and surface support elements. Connectivity refers to the capacity of a system to transfer the dynamic load from an element to another, for example, from the reinforcement to the surface support through plates and terminating arrangements...

Coal burst is a manifestation of rapid energy release, which is considered as one of the most critical operational hazards in underground coal mines. This study numerically investigates the effects of discontinuities on the strength and energy release characteristics of coal mass samples under uniaxial compression. The universal distinct element co...

This paper investigates the anisotropy of coal under uniaxial compression conditions using both experimental and numerical methods. Primary wave (P-wave) velocity measurements, X-ray micro-computed tomography (CT) scanning, and uniaxial compression tests were conducted to assess the anisotropic characteristics of selected coal samples. Based on the...

This paper presents a new criterion for assessing top coal cavability in Longwall Top Coal Caving mining technology. Top coal Cavability Index (TCI) criterion was developed through a parametric study, statistical analysis and validation against field monitoring data. A discontinuum modelling technique with plastic rock material was used to quantify...

Coal burst has been increasingly attracting attention in Australian coal mines recently as they go deeper. Coal burst is well known for its catastrophic destruction, complex mechanisms and difficulty of control in the mining industry. This paper summarises the control measures used globally for this dynamic failure, and shows how to develop site sp...

Safety is the highest priority in the mining industry as underground mining in particular poses high safety risks to its workers. In underground coal mines, coal bursts are one of the most catastrophic hazards, which involves sudden and violent dynamic coal mass failure with rapid ejection of the broken material into the mine workings. Despite deca...

The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures and changes of coal thickness can help identify zones prone to rock bursts to improve safety and productivity in coal mines. This st...

Coal joints and cleats are geological discontinuities that are the most important factors that affect the mechanical responses of a coal mass under stress. The joint and coal mass interaction and the mode of failure dominate the mechanical behaviour of jointed coal masses, and therefore the stability of coal excavations. The shear or mixed shear/te...

Designing reliable yielding support system to mitigate the effect of the kinetic energy in burst-prone conditions in mining and tunneling excavations is one of the challenges for geotechnical engineers. A combination of the support elements can be used to increase rock strength and minimise the displacement of unstable rock mass. It is important to...

Longwall Top Coal Caving (LTCC) is a thick coal seam mining method which uses the Single Pass Longwall (SPL) method for extracting the lower section while the upper section (top coal) is mined by means of caving. The mining height in LTCC, compared to other methods, may result in roof instabilities such as caving and weighting. The understanding of...

Geomechanical and geotechnical characteristics of coal seam are important parameters that directly affect the cavability of top coal in the longwall top-coal caving (LTCC) method. The impact of these parameters such as coal strength, coal deformation modulus, coal discontinuities and top-coal thickness on cavability has not been fully understood in...

The successful application of Longwall Top Coal Caving (LTCC) method is largely dependent on the cavability of top coal. In conjunction with coal seam, overlying strata are believed to affect the top coal cavability. Based on an Australian LTCC operation, the study focusses on investigating the effect of immediate and main roof strata on the top co...