Junlong Shang

University of Glasgow | UofG · School of Engineering

Granite formations have been frequently involved in subsurface energy-related activities such as radioactive waste disposal, oil, and gas storage. This is principally because of their mechanical stability, low permeability, and high corrosion resistance. These favorable properties, however, can be compromised by the addition of mineral veins, which...

Geological discontinuities have a controlling influence for many rock-engineering projects in terms of strength, deformability and permeability, but their characterisation is often very difficult. Whilst discontinuities are often modelled as lacking any strength, in many rock masses visible rock discontinuities are only incipient and have tensile s...

True persistence of rock discontinuities (areas with insignificant tensile strength) is an important factor controlling the engineering behaviour of fractured rock masses, but is extremely difficult to quantify using current geological survey methodologies, even where there is good rock exposure. Trace length as measured in the field or using remot...

This paper presents a numerical investigation of the effects of boundary conditions, i.e., constant normal load (CNL) and constant normal stiffness (CNS), on the failure mechanism of incipient rock discontinuities in direct shear. A series of numerical simulations were performed using the particle-based discrete element method (DEM), in which rock...

Cryptocrystalline flint is an extremely hard siliceous rock that is embedded in chalk formations, which in recent decades is often used as a host for underground rock caverns and tunnels in Europe and North America. A reliable estimation of the uniaxial compressive strength (UCS) of the extremely strong flint, with an average UCS of about 600 MPa w...

Multi-seam mining often leads to the retention of a significant number of coal pillars for purposes such as protection, safety, or water isolation. However, stress concentration beneath these residual coal pillars can significantly impact their strength and stability when mining below them, potentially leading to hydraulic support failure, surface...

Layered and heterogenous fissured rock masses are ubiquitous in nature. Fissures exert significant influence as release surfaces and nucleation sites for failure in layered rock masses. However, key mechanisms controlling microcrack initiation and extension in layered and heterogenous rock masses remain unclear. We complete a suite of numerical (gr...

In deep rock engineering, the stability of the rock is a key factor [...]

To probe the difference between static-driven and dynamically triggered rockbursts, three types (static-driven rockburst, SDR; pulse-disturbance rockburst, PUDR; period-disturbance rockburst, PEDR) of true triaxial unloading rockburst tests were carried out on marble. The rockburst characteristics were compared and analyzed through five distinct as...

Although rock mechanical behaviour has a long record of study, attempts to understand the role of fractures on rock deformation still have unresolved issues. Due to technical and/or economic challenges, natural rock fractures are often dealt with crudely, without detailed consideration of fracture geometry and heterogeneity in many geoscience appli...

Multistage constant-amplitude-cyclic (MCAC) loading experiments were conducted on Tibet interbedded skarn to investigate and characterize fatigue mechanical behavior of the tested rock. Rock volumetric deformation, stiffness change, and fatigue damage evolution were analyzed along with the macroscopic failure morphology. The experimental results de...

What hinders current models for fluid transportation in three-dimensional (3D) fracture system from considering fracture roughness is model complexity, which makes it hard to get convergent results. Therefore, we propose an electrical circuit (EC) model to simulate fracture flow, with each rough rock fracture taken as an EC with distributed electri...

This paper analyzed the pore structure, quantified the pore fractal dimension, calculated the grading index (GI) of mixed aggregate, and studied the relationship among GI, pore structure, and strength to describe the cross-scale characteristics of backfill, which is made from stone powder and cemented tailing. A series of experiments were conducted...

Rocks in cold regions tend to experience exacerbated degradation under the combined effects of environmental and anthropogenic factors, which may arise from, for example, temperature fluctuation, mechanical excavation, and blasting. Activities related to rock support or open-pit slope optimization in cold regions require a complete understanding of...

Pile punching (or driving) affects the surrounding area where piles and adjacent piles can be displaced out of their original positions, due to horizontal loads, thereby leading to hazardous outcomes. This paper presents a three-dimensional (3D) coupled Smoothed Particle Hydrodynamics and Finite Element Method (SPH-FEM) model, which was established...

Opening holes in rock including their size and distribution can affect the performance of rock-related structures. A good understanding on this will contribute to, for example, rock cavern design, and construction, tunnelling, and mining engineering. To improve the understanding, a comprehensive investigation of the opening hole effect on the rock...

This paper presents a 3D coupled Smoothed Particle Hydrodynamics (SPH) and Finite Element Method (FEM) model, which was developed to investigate the extent of damage zone and fracture patterns in rock due to blasting. The RHT material model was used to simulate the blasting-induced damage in rock. The effects of discontinuity persistence and high i...

A complete understanding of the fracture behaviour of anisotropic rocks under elevated temperatures is fundamentally important for rock and reservoir engineering applications. This paper shows a three-dimensional numerical investigation of the fracture behaviour of anisotropic sandstone, with consideration of the effects of temperature and material...

Apertures of rock fractures is frequently considered as one of the most important factors affecting grouting characteristics. The real fracture distribution, however, is inaccessible due to its complex intrinsic properties, making it cumbersome to directly assess its impact on on-site grouting. In this paper, we argued that investigation of the gro...

The pore structure and porosity of three kinds of mine grouting materials were characterized based on a thin-section analysis and low-field nuclear magnetic resonance (NMR) technique. The macroscopic pore interconnectivity was investigated using binary images captured from thin sections and a random walk pore spectral dimension (RWPSD) algorithm. T...

The bonding condition at the rock and rockbolt interface is one of the most important factors to determine the load transfer mechanism of a CMC rockbolt element. The two-dimensional Discontinuous Deformation Analysis (2D-DDA) method is used in this paper to investigate the pullout performance of the CMC rockbolt element which is modeled as three co...

A 3D particle-based DEM model was established taking into account the geometries of rock bridges. The model was used to investigate the shear behaviour of incipient rock joints. Fifty-seven direct shear tests were conducted under constant normal load (CNL) boundary conditions using the established model, in which rock bridges with nineteen differen...

Due to scarce land resources in Singapore, it is imperative to increase water storage capacities to meet the increasing demand of water to secure a sustainable development, which can be achieved in the underground by rock caverns. In this paper, a preliminary study on the effects of cavern span, height and radius on the cavern stability is presente...

The advanced door lock system is not as safe as it is claimed, using coded card and card reader system to ensure your the safety of your home or office. The unsafe place is also the system itself, as shown in our system, we can develop a system to open the door without any encoded or endorsed card. We utilize a remote controller to send signal to t...

In this paper, a testing methodology was developed in the laboratory to measure the tensile strength of large-scale incipient rock joints. In the test, an expansive grout was used to develop the tensile force. Each test comprises two phases: Phase i test and Phase ii test. The Phase i test identified sample failure time, while the Phase ii test mea...

This figure is related to the article entitled "3D particle-based DEM investigation into the shear behaviour of incipient rock joints with various geometries of rock bridges" which has been published in RMRE 2018, https://doi.org/10.1007/s00603-018-1531-0

This figure is related to the article entitled "3D particle-based DEM investigation into the shear behaviour of incipient rock joints with various geometries of rock bridges" which has been published in RMRE 2018, https://doi.org/10.1007/s00603-018-1531-0

Stresses induced by a demolition agent in non-explosive rock fracturing was analysed using the theory of elasticity and the thick-walled cylinder principle. Circumferential and radial stresses in rock induced by an internally pressurized hole was first analysed under plane strain condition. Stresses perpendicular to the line connecting two adjacent...

Persistence of geological discontinuities is of great importance for many rock-related applications in earth sciences, both in terms of mechanical and hydraulic properties of individual discontinuities and fractured rock masses. Although the importance of persistence has been identified by academics and practitioners over the past decades, quantifi...

Index tests (such as point load and Schmidt hammer tests) have been widely used to estimate the unconfined compressive strength (UCS) of rock because of the straightforward testing setup and procedures. However, results of the index tests may vary due to lithological heterogeneity; validity of the tests remains poorly understood. In this study, a s...

This paper relates to thermal effect on the fracture toughness of a Midgley Grit sandstone. A 3D semi-circular bend (SCB) model of the rock incorporating thermal responses of different minerals was established using the particulate Discrete Element Method (DEM). The particulate DEM model was calibrated against a laboratory programme. The results re...

The anisotropic direct tensile behaviour of laminated and transversely isotropic Midgley Grit sandstone (MGS) was investigated in this paper using a particle-based discrete element method (DEM) with consideration of the incipiency of bedding planes. Laboratory experiments were conducted to quantify the direct tensile strength of the incipient beddi...

Rock discontinuities are fundamentally important to most rock engineering projects but predicting or measuring their properties such as roughness, aperture, shape and extent (persistence) are fraught with difficulty. So far the solution of how to measure or predict persistence is poorly researched partly because the concept of how to investigate th...

Geological discontinuities have a controlling influence for many rock-engineering projects in terms of strength, deformability and permeability, but their characterisation is often very difficult. Whilst discontinuities are often modelled as lacking any strength, in many rock masses visible rock discontinuities are only incipient and have tensile s...

Generally, rock discontinuity develops from an original incipient state with a high tensile strength to fully mechanical discontinuities with zero tensile strength (Hencher & Knipe, 2007). Incipient discontinuities have a controlling influence on many projects in terms of strength, deformability and permeability. For engineering simplification purp...

This paper addresses the issue of the tensile strength of incipient discontinuities in rock and presents preliminary results from a series of laboratory studies. In most rock masses rock discontinuities, as veins or incipient fractures, often retain some tensile strength that may approach that of the parent rock. This fact is of high importance to...

Porosity increment and strength degradation of low-porosity sedimentary rocks under different loading conditions

In order to precisely predict the hazard degree of goaf (HDG), the RS-TOPSIS model was built based on the results of expert investigation. To evaluate the HDG in the underground mine, five structure size factors, i.e. goaf span, exposed area, goaf height, goaf depth, and pillar width, were selected as the evaluation indexes. And based on rough depe...

There exist complicated non-linear relations between explosive vibration effect and its affecting factors, and accurate prediction of the attenuation law of blasting vibration is the basis of blasting design and disaster control. Based on the analysis of defects of traditional Sadaovsk formula, a modified Sadaovsk formula (MSF) considering the heig...

To investigate the influence of rock heterogeneity on mechanical properties, RFPA2D used for analysis of rock failure process is applied to study the damage evolution mode and acoustic emission characteristic of rocks with various kinds of heterogeneity(m=1.0,3.0,5.0,10). The results shows that rock heterogeneity has remarkable influence on its mec...

Based on the improved matter-element extension theory, an improved matter-element extension model used to predict the rockburst intensity was established. Firstly, the main factors of rockburst intensity, such as the maximum tangential stress of the cavern wall σθ, uniaxial compressive strength σc, uniaxial tensile strength σt, and the elastic ener...

There exists complicated non-linear relations between explosive vibration effect and its affecting factors, and accurate prediction of the attenuation law of blasting vibration is the basis of blasting design and disaster control. Based on the analysis of the defects of traditional Sadaovsk Formula, Modified Sadaovsk Formula(MSF) considering the he...

In this paper, in order to improve the present methods of rock blastability classification, a prediction model of game theory-matter-element extension for blastability classification was established. Firstly, based on the analysis of main causes of blastbility, three indexes were chosen as the evaluation indicators and the classification standards...

Advanced predication of geological anomalous body (GAB) of laneway can provide scientific references for mine safety production. It refers to reveal the position, shape and size of GAB in advance. Seismic tomography technology (STT) can realize the prediction of GAB using tunnel surface waves. Tunnel Reflection Tomography (TRT) 6000 system, which i...

A method of technique for order preference by similarity to ideal solution (TOPSIS) was used to classify the quality of the rock mass in underground engineering. Five indexes, i.e., rock quality designation, uniaxial compressive strengthen, rock mass integrality coefficient, strengthen coefficient of structural plane and seepage measurement of grou...

There have many open pits in China threatened by cavities under open pit limit. The key to insure safe mining depends on the thickness of safety isolation layer between cavity and bench surface, and it needs to be solved urgently with the steps of bench blasting. Based on the present situation of Dabaoshan mine which is an open pit with lots of har...