Disturbances owing to coal mining result in the movement and failure of floor strata. Mining-induced fractures within the floor may propagate to the confined aquifer, thereby causing water inrush disasters. In this study, we propose using strip mining and backfill replacement mining above the confined aquifer to investigate the failure depth of the floor. The problem is simplified as a distributed

The borehole sealing material is one of the key factors affecting the gas drainage effect of a borehole. This paper takes the compressive strength, fluidity, expansion rate, and setting time of the sealing material as the main research indicators and explores the influence of each key influencing factor on the performance of the high-fluid sealing material through the single factor experiment method

“Smart growth” is an urban planning concept. In this paper, the overall urban-rural smart growth efficiency is explored, which serves as an indicator to effectively measure the allocation of urban-rural spatial resources and structural rationality of the urban-rural space. Taking a developing county city in northwest China plains area as an example, the urban-rural spatial efficiency system was established

Landslides induced by engineering construction are very common in reality; it is necessary to clarify the causes of landslide failure to avoid similar accidents. A landslide induced by highway construction is taken as a case. Field observations, data collection, and analyses were used to investigate the deformation and causes of the landslide. The failed slope is mostly comprised of gravel soil, there

To study the influence of consolidation stress ratio and stress history on 1-D consolidation permeability of saturated clay, one-dimensional consolidation permeability tests were carried out with GDS triaxial device. The results indicated that the permeability coefficient and void ratio of normally and overconsolidated saturated clay decreased with the increase of consolidation stress ratio under different

Rock burst is a serious nonlinear dynamic geological hazard in underground engineering construction. In this paper, a true triaxial unloading rock burst experiment and numerical simulation are carried out on Tianhu granite to investigate the rock burst tendency and crack development characteristics of surrounding rock after excavation. The experiment and numerical simulation process monitored the rock

Spontaneous water imbibition is an important mechanism in water-wet fractured reservoirs. For volume-fractured reservoirs, to evaluate the oil productivity and oil recovery through water counter-current imbibition, we propose an analytical method for optimizing the reservoir volume fracturing scheme. Based on the two-phase fluid flow differential equation for capillary force, a three-dimensional water

The forming of micro or mesocracks on rock surfaces is a symptom and precursor of the degradation of deep surrounding rocks under excavation. However, the direct detection or observation of these tiny developed cracks is not practical due to the limitation of current instruments which can only capture and recognize macrocracks. Therefore, many indirect detection ways are proposed to acquire some precautional

Surrounding rock pressure, water pressure, and joint roughness are the important factors that affect the fractured rock mass seepage. It is of great significance to quantify the influence of these factors through experiments. In this study, rock fracture joint surfaces were measured. Next, 3D coordinates of joint surfaces were extracted with using the Geomagic software, and joint roughness was described

Solid backfill coal mining (SBCM) is a green mining technology which can effectively alleviate the environmental problems induced by traditional coal mining techniques, such as surface subsidence, water resources loss, coal gangue occupation, and pollution. In this study, a multilayer Winkler foundation beam model for the overburden key strata is proposed, and the model with two key strata is solved

To explore the effect of different bend pipes on the propagation characteristics of premixed methane-air explosion, the experimental explosion pipe system and numerical model were established. By adopting the comparative analysis of experiments and numerical modeling, it conducted researches on the overpressure evolution of gas explosion shock wave in pipes with different bends and obtained the expressions

The difficulty of deploying remaining oil from unconventional reservoirs and the increasing CO2 emissions has prompted researchers to delve into carbon emissions through Carbon Capture, Utilization, and Storage (CCUS) technologies. Under the confinement of nanopore in unconventional formation, CO2 and hydrocarbon molecules show different density distribution from in the bulk phase, which leads to a

The Paleozoic strata are widely distributed in the northwest of the Ordos Basin, and the provenance attributes of the basin sediments during this period are still controversial. In this paper, the detrital zircon LA-MC-ICPMS U-Pb age test was conducted on the drilling core samples of the Shanxi Formation of the Upper Paleozoic in the Otuokeqi area of the Ordos Basin, and the provenance age and the

Classical theoretical approaches to evaluate CPTU-based hydraulic conductivity gave the expression of a bilinear relation defined by -, for undrained and drained soils. In fact, a dividing line may be selected with a certain degree of subjectivity, and several undrained/drained points occur in opposite sites, which may make us doubt the necessity of two intersecting lines to distinguish the undrained

There are many karst collapse columns in coal seam roof in the southern coal field in China, which are different from those in coal seam floor in the northern coal field, due to the stratum characteristics. The karst collapse column in coal seam roof tends to reactivate and conduct water and induce the serious water inrush disaster, when the karst collapse column communicates with the overlying aquifer

Aiming at the seismic response of plastic geogrid-reinforced embankments, with Zhounan Expressway as the research engineering background, a self-designed seismic-rainfall coupled slope model test system was designed and used to produce 1 : 20 scale plastic geogrid-reinforced embankments. Moreover, the physical model of the unreinforced embankment under Hanshin wave, Wenchuan wave, Tianjin wave, etc

Grouting is always used in mine water plugging, reinforcement, and other disaster prevention projects. The diffusion mechanism of slurry in fractured rock is affected by geological environment and slurry performance, which should be revealed and characterized better. Based on the two-phase flow diffusion theory, a slurry diffusion model considering flowing water condition was established for a blocking

The unconventional resources from an ultradeep tight gas reservoir have received significant attention in recent decades. Hydraulic fracturing is the main method for tight gas reservoir development because of its extremely low permeability and porosity. During hydraulic fracturing, high hydraulic fracturing fluid (HFF) that invaded the zone near the fracture face may reduce gas relative permeability

Gas outburst is an important issue in deep coal mining. At present, the gas-rock coupling change mechanism and intensity prediction of gas outburst are not clear. The research of gas outburst simulation experiment is particularly important. The State Key Laboratory of Gas Disaster Monitoring and Emergency Technology of China independently developed a large-scale coal and gas outburst physical simulation

With the steady increase in the size, intensification, and modernization of coal production enterprises, the deep coal resources in large coal bases are gradually entering the mining stage. When the coal mining reaches the deep zone, the interactions between various underground dynamic hazards begin to occur. These interactions are affected by the engineering geological environment and can lead to

Optimization of the depressurization pathways plays a crucial role in avoiding potential geohazards while increasing hydrate production efficiency. In this study, methane hydrate was formed in a flexible plastic vessel and then gas production processes were conducted at constant confining pressure and constant confining temperature. The CMG-STARS simulator was applied to match the experimental gas

The occurrence of unconformity-related uranium mineralization requires the combination of three components: fluids with the right composition, geochemical traps with the right agents that produce precipitation, and structural traps with the right geometry. In the Athabasca Basin unconformity-related uranium deposits, while basinal brines are commonly accepted as the principal mineralized fluids and

The stability and safety of underground rock mass engineering are closely related to the permeability process of fluids and permeability properties of rocks. To reveal the flow behavior of fluid in thermal damaged rock, first, a rock seepage testing system was applied to study the permeability properties of red sandstone specimens after different high-temperature treatments from 200 to 800°C under

Whether intentionally or unintentionally, waterflooding always takes place under fracturing condition in tight reservoir because of the extremely limited water absorption ability of the formation. Recently, we proposed a novel workflow, including real-time monitoring, formation testing analysis, and dynamic production analysis, to timely and effectively identify the initiation of waterflood-induced

The shale of the Lower Silurian Longmaxi Formation is an important gas-producing layer for shale gas development in southern China. This set of shale reservoir characteristics and shale gas development potential provide an important foundation for shale gas development. This study takes wellblock XN111 in the Sichuan Basin, China, as an example and uses X-ray diffraction (XRD), scanning electron microscopy

The shale oil of the Lucaogou Formation in the Jimusaer Sag of the Junggar Basin was divided into two sweet spots for exploration and development. Crude oil in the upper and lower sweet spots comes from the upper and lower source rocks. After years of exploration, it has been found that the crude oil in the lower sweet spot has worse physical properties than that of the upper sweet spot. In this study

Cutting force is the key signal to realize intelligent control of shearer and mastering the change process of cutting force is helpful to improve the adaptive cutting of shearer. In this paper, full scale rock cutting tests are used to carry out single pick cutting experiments on three kinds of coal, and the acoustic emission (AE) signals of coal and rock cutting are monitored in the whole process

Based on this, the slope stability and disaster law under the condition of heavy rainfall are studied. With the slope of Shangge Village as the background, the slope stability under the condition of heavy rainfall is deeply studied through theoretical analysis, laboratory physical model experiment, and numerical simulation. Results showed that due to the heavy rainfall within 2 h, the deformation of

The theory of coalbed methane distribution controlled by tectonism is a hot issue in the field of geofluid-geotectonic interaction research. Taking the geological structure in the scale range of the 1302 working face of a Guojiahe wellfield in a Yonglong mining area as the background, this paper focuses on the basic research problem of the influence of geological structure on the control of coal reservoir

A rock burst usually causes a roadway collapse or even an instant blockage. When the deformation energy accumulated in the surrounding rock exceeds the minimum energy required for the dynamic destruction of the surrounding rock of a roadway, a rock burst accident will occur. According to statistics, 85% of rock burst accidents occur in roadways. This paper establishes a strong-soft-strong structural

In recent years, sand production has been frequently observed in offshore weakly consolidated sandstone reservoirs. Permeability changes due to sand migration seriously affect the confidence in well test interpretation, production forecasts, and oilfield development plan schedules. The purpose of this paper is to propose a comprehensive model of coupled sand migration, stress sensitivity, and high

Nonmagmatic, carbonate-hosted epigenetic hydrothermal Pb–Zn deposits similar to those at the Huize Pb–Zn Mine are widespread across the Sichuan–Yunnan–Guizhou (SYG) polymetallic province. The precipitation mechanisms of these geologically intriguing deposits are an area of interest for many researchers. To simulate the underlying precipitation reaction mechanisms and dynamics of each aspect, a fluid

As a new type of waterproof curtain, several station construction of Qingdao Metro Line 1 successfully used the trench cutting remixing deep wall (TRD). It is difficult to find the factors that affect the wall quality because the method is in situ underground excavating and mixing. This paper has obtained the main factors affecting the TRD quality in Qingdao by studying construction experience and

The temporal permeability and damage evolutions of low-permeability sandstone cores during triaxial and long-term dissolution experiments were measured using a triaxial-flow system. Three triaxial experiments were performed on sandstone cores having initial permeability ranging from to . Two sets of long-term dissolution experiments were conducted on cracked sandstone cores. All dissolution experiments

The character of residual oil formed during water flooding, one important technique to enhance oil recovery, is helpful to further study permeability and recovery in tight sandstone oil reservoirs. In this paper, we take a tight sandstone reservoir in Ordos Basin as the research object and use in situ displacement X-CT scanning technology to analyze the dynamic characteristics of oil during water flooding

Sand-based cemented backfill (SBCB) mining technology is instrumental in utilizing coal resources buried under the water bodies. SBCB is exposed to the long-term action of mining-induced stresses in the goaf and groundwater permeating via microcracks along the rock strata. Studying the permeability evolution of SBCB under varying stress states is crucial for protecting coal and water resources below

The thick and hard rock strata (THRS) exist widely in coal measure strata, which control the movements of overlying rock strata in stopes. When THRS break, great energy is released, which could aggravate the risks of coal and gas outburst, rock burst, and other dynamic disasters. Therefore, the foundation and key of preventing dynamic disasters are to distinguish the THRS that could induce coal-rock

Pore water pressure has an important influence on the stresses and deformation of the surrounding rock of deep tunnels in water-rich areas. In this study, a mechanical model for deep tunnels subjected to a nonuniform stress field in water-rich areas is developed. Considering the pore water pressure, a new unified solution for the stresses, postpeak zone radii, and surface displacement is derived based

Naturally fractured rock mass is susceptible to stress disturbance and could result in the stimulation of natural fractures and even serious geological hazards. In this work, multilevel uniaxial fatigue loading experiments were carried out to reveal the fracture and energy evolution of naturally fractured granite using stress-strain descriptions and energy evolution analysis. Results reveal the influence

Surfactant polymer (SP) flooding has become an important enhanced oil recovery (EOR) technique for the high-water cut mature oilfield. Emulsification in the SP flooding process is regarded as a powerful mark for the successful application of SP flooding in the filed scale. People believe emulsification plays a positive role in EOR. This paper uses one-dimensional homogenous core flooding experiments

The rock burst must be generated by energy. In order to explore the distribution law of energy in coal-rock system, based on the structural characteristics of coal and rock and the mechanical characteristics analysis of coal-rock combined body model, the calculation formula of energy distribution was given before the damage of same diameter coal-rock combine body and nonsame-diameter coal-rock combined

As gasoline is the main fuel of small vehicles, the exhaust emissions from its combustion will affect air quality. The focus of gasoline cleaning is to reduce the sulfur and olefin content in gasoline while maintaining its RON as much as possible. The reduction of RON will bring great economic losses to enterprises. Therefore, it is very important for petrochemical enterprises to construct a RON loss

Shale reservoirs have some natural fractures with a certain density and connectivity. The basic percolation model of shale gas reservoir: the black oil model of gas-water phase is used as the basic model, and the dissolved gas is used to simulate adsorbed gas. Accurate description of natural fractures: random distributed discrete fracture model is used as the basic model to describe natural fractures

Reasonable depth of pile embedment is one of the key factors for the success of deep foundation pit projects. This paper has taken a deep foundation pit project in a granite residual soil area in Shenzhen as an example and used physical model tests to study the deformation law of the piles and the surrounding soil during the excavation of the deep foundation pit, revealing the variation law of earth

Formation damage usually occurs in near-well regions for injection wells completed in offshore oilfields under the development of line drive patterns. However, current works on characterizing the damage by well test analysis were basically focused on using single-phase analogy to solve two-phase flow issues, resulting in errors on the diagnosis and interpretation of transient pressure data. In this

Slope structures and surface terrains are two significant factors affecting the deformation behavior of mining slopes in mountainous areas. This research is aimed at investigating the deformation characteristics of a mining slope wielding Particle Flow Code (PFC), with 9 different mining configurations (i.e., horizontal distance from extracted panel center to slope shoulder, D = −200 m, −150 m, −100 m

In recent years, bed separation water inrush, as a new type of water disaster, has posed serious threat to mining safety in China’s many coal mines. This study focused on periodic water inrush accidents in the No. 7335 working face owned by Xuzhuang Coal Mine, Jiangsu Province, China. Based on the theory of key strata, the formation positions of the separation layer in the overlying strata were first

The analysis of energy dissipation characteristics is a basic way to elucidate the mechanism of coal rock fragmentation. In order to study the energy dissipation patterns during dynamic tensile deformation damage of coal samples, the Brazilian disc (BD) splitting test under impact conditions was conducted on burst-prone coal samples using a split Hopkinson pressure bar (SHPB) loading system. The effects

One of the challenges indigenous microbial enhanced oil recovery (MEOR) is facing is the high percentage of divalent ions, which obstruct the growth and metabolism of microorganisms and destabilize the oil-in-water (o/w) emulsion. Six formulas were selected for the stimulation of indigenous microbes and to compare their performances on the oil emulsification and oil spreading in the Luliang oilfield

Mine water inrush seriously threatens the safety of coal mine production. Quick and accurate identification of mine water inrush sources is of great significance to preventing mine water hazards. This paper combined partial least squares-discriminate analysis (PLS-DA) with inrush water chemical composition to identify the source of water inrush from multiple aquifers in mines. The Renlou Coal Mine

Coal seam water injection is an important technical method to prevent and control coal and gas outburst and other disasters. Water can soften coal and change its mechanical properties. In order to study the mechanical properties of coal samples with different moisture content, briquette coal samples with five moistures content (4%, 6%, 8%, 10%, and 12%) were selected to carry out triaxial compression

Finding out the reasons for wellbore instability in the Longmaxi Formation and Wufeng Formation and putting forward drilling fluid technical countermeasures to strengthen and stabilize the wellbore are very crucial to horizontal drilling. Based on X-ray diffraction, electron microscope scanning, linear swelling experiment, and hot-rolling dispersion experiment, the physicochemical mechanism of wellbore

When the mountain tunnel projects passing through the complex formation with coal, it happened along with disaster accidents such as gas outburst, gas combustion, and gas explosion. These disasters should seriously threaten the safety and life of the construction personnel and affect the normal operation of the tunnel construction. Ventilation is the most effective means to control gas, fire, dust

Due to the diversity of pore types, it is challenging to characterize the Middle East’s Cretaceous carbonate reservoir or accurately predict its petrophysical properties. In this paper, pore structure in the reservoir is first classified using a comprehensive method. Then, based on the identified pore structure types, a new permeability model with high prediction precision is established. The reservoir

The hysteresis of water-sediment mixture seepage in rock fractures is one of the critical factors which affect the determination of the timing of coal mine water inrush disasters prevention and control. In this paper, a mechanical model was established to study the hysteresis whose criteria were also put forward. The area of the hysteresis loop and the maximum pressure gradient were selected as characterization

Multiseam coalbed methane (CBM) exploitation can not only reduce single-well investment but also increase the length of service of the well and significantly enhance the CBM economic recovery of the entire basin. To compare with and further to guide the actual project of CBM production, this study proposed a conceptual gas-water two-phase separate flow model for single coal seam considering the solubility

Ice-driven mechanical weathering in cold regions is considered a main factor impacting the stability of rock mass. In this work, the response surface method (RSM) was employed to evaluate and optimize the multiple frost heaving parameters to seek the maximum frost heaving force (FHF), in combination with experimental modeling based on a specially designed frost heaving force measurement system. Three

Deep roadway deformation due to soft rock, rock dip, and horizontal tectonic stress is uneven and asymmetrical primarily in large loose zones. Traditional anchor support is influenced by the yield strength and shear strength of the anchors and has a limited prestress capacity or shear resistance. When the roadway roof is laminated rock or when the roadway passes through layered rock or rock interfaces

Throughout engineering construction, large deformation disasters in soft rock tunnels are encountered increasingly frequently. Therefore, structural health monitoring not only ensures accurate construction management but also provides a basis for dynamic adjustment of the support structure. The existing monitoring technology has certain shortcomings, such as poor anti-interference ability, non-real-time

Deep excavations are intensively carried out in many cities in China and other countries. One of the major loadings in such construction work is the water pressure, and great effort is required to assess the seepage problem and the corresponding water pressure on the retaining wall for a good design and construction. Different methods used for the seepage analysis are discussed in this paper through