Rock In Deep Roadway Research Articles

Similar ratio experiment and characteristic analysis of quasi-sandstone

The stability control of surrounding rock in deep roadway is becoming more and more difficult, and grouting reinforcement support has become the mainstream of roadway control. In order to obtain the ratio of quasi-sandstone material corresponding to the grouting body, this paper uses river sand as aggregate, cement and gypsum as cementing agent, retarder and defoamer as additives, and carries out orthogonal proportioning tests with three influencing factors: water-binder ratio (ratio of water to mass of cementing agent), gypsum-cement ratio (ratio of gypsum to mass of cement) and binder-aggregate ratio (ratio of cementing agent to aggregate mass), and compares and analyzes the sensitivity of each factor on the density, compressive strength, tensile strength, elastic modulus, Poisson’s ratio, longitudinal wave velocity, elasticity index and brittleness index of quasi-sandstone material. The results show that 1) the Water-binder ratio has the greatest effect on the sensitivity of material compressive strength, tensile strength, elastic modulus, Poisson’s ratio and longitudinal wave velocity; the gypsum-cement ratio has the greatest effect on the sensitivity of material deformation index and brittleness index; the binder-aggregate ratio has the greatest effect on the sensitivity of material density. 2) Reducing the Water-binder ratio can improve the density, compressive strength and tensile strength of the material; reducing the paste ratio can improve the modulus of elasticity, Poisson’s ratio and longitudinal wave speed of the material; as the gypsum-cement ratio increases, the deformation index first decreases and then increases and then decreases; as the binder-aggregate ratio increases, the brittleness index first increases and then decreases and then increases. 3) The empirical equations between physical and mechanical properties of sandstone-like materials and Water-binder ratio, gypsum-cement ratio and binder-aggregate ratio were established based on multiple linear regression analysis, and more reasonable material ratios were quickly obtained by physical and mechanical parameters of materials. The results of the study provide theoretical references for similar material simulation tests for quasi-sandstone grouting.

Integrated Collaborative Control of “Shielding-Filling-Grouting” of 1 km Deep Large-Section Roadways: A Case Study

Effective control of deformation failure of surrounding rock in deep roadway has become an important prerequisite for the safe and efficient development of deep coal resources. In this study, the field measurement of the study area’s in-situ stress was carried out for the specific engineering geological conditions of the KCM −967 m level west-wing main track roadway. The west-wing main track roadway’s full-section deformation failure features were summarized and analyzed, and the main roadway’s surrounding rock nonlinear deformation failure mechanism was revealed from the perspective of elastoplastic mechanics. Based on that, a set of highly targeted integrated collaborative control technology of “shielding-filling-grouting” system was proposed. The industrial field test revealed that, after the above integrated collaborative control scheme was adopted, there was no strong deformation failure on the surface of the main roadway surrounding rock and deep rock mass, which played the role of active and passive support collaborative control, reduced the subsequent repeated repair and maintenance workload of the roadway, and satisfied the needs of long-term safe and efficient production of the mine. The results obtained provide a reference for the control of surrounding rock of deep and large-section roadways in other mining areas.

Research on Pressure Relief Method of Close Floor Roadway in Coal Seam Based on Deformation and Failure Characteristics of Surrounding Rock in Deep Roadway

To solve the high-stress hazard faced in the process of deep mining process, the pressure relief characteristics of gas bearing coal and the deformation characteristics of surrounding rock in deep roadway are studied by means of laboratory test, similar simulation analysis, and field investigation. The investigation results and engineering application showed that the specimens could more easily reach the failure point due to the axial pressure relief under high confining pressure. In addition, the deformation and failure degree of the surrounding rock was higher due to the disturbance from the deep high-stress roadway. The scope of the height affected by the pressure relief of the overlying strata reached above 10 m. Moreover, the initial gas emission could reach 4.41–14.39 times that of the original coal seam by drilling a hole in the coal seam at 10 m from the roof. Thus, the short-distance floor roadway exerted an obvious pressure relief effect on the overlying coal seam.

Asymmetric deformation characteristics and support scheme design of the surrounding rock in deep roadway

Aiming at the asymmetric deformation of the surrounding rock in the deep roadway, five typical influencing factors of asymmetric deformation have selected: dip angle, buried depth, lithology, lateral pressure coefficient (λ), and height-width ratio (Rdw). Taking the surface displacement of the surrounding rock as the measurement index, a method of monitoring and recording the deformation of the full-section node of the roadway has proposed to investigate the surface deformation law of the full-section surrounding rock of the roadway. Based on 25 sets of orthogonal tests, the asymmetric distribution characteristics of surrounding rock deformation under single factor and multiple factors were studied, respectively. The full cross-sectional distribution characteristics of surrounding rock deformation and the main influencing factors of the asymmetric distribution of deformation have got. The most remarkable asymmetric deformation occurs when the dip angle is 45°. λ and Rdw significantly influence the asymmetry of the deformation. The coupling relationship between influencing factors has discussed. Based on the level of influencing factors, we briefly gave the prediction of asymmetric deformation of the surrounding rock of the roadway. Closed support measures can significantly reduce the asymmetry of the surrounding rock surface deformation. Combined with the design and optimization of the roadway support scheme, the asymmetric deformation of the surrounding rock has been controlled. This research can provide references for the understanding of the failure characteristics of the surrounding rock in deep inclined formations and the design of deformation control and support schemes.

Research on Surrounding Rock Control Technology of Dongbaowei Deep Mining Roadway

In order to explore the stability control of surrounding rock in the process of deep mining, comparative analysis of stress, deformation, and fracture characteristics of surrounding rock of deep and shallow mining roadway in dongbaotou coal mine, laboratory experiments, field measurement, numerical simulation, and field industrial experiments were adopted to put forward the control plan of the surrounding rock in deep roadway, which were verified by field industrial experiments. The results of laboratory experiments and field experiments show that the mechanical properties of deep roadway surrounding rock of Dongbaowei Coal Mine are significantly lower than those of the shadow roadway, mainly due to the development of joints and fractures of the overlying strata in the deep stope, serious impact on the disturbance of the roadway which has been made by the strong pressure of the stope, and reduced crushing strength of surrounding rock. Through comparative analysis of deep roadway support plan carried out by numerical simulation, the support scheme suitable for Dongbaowei Coal Mine is put forward, which is applied in the field. Field industrial experiments show that after the optimization of support parameters, the deformation of surrounding rock of roadway is well controlled. The displacement of surrounding rock of roadway is basically stable after 10∼15 days. The support of surrounding rock of roadway has good effect, which achieves the goal of stability control of deep roadway surrounding rock.

Experimental Study of the Failure Mechanism of the Anchorage Interface under Different Surrounding Rock Strengths and Ambient Temperatures

In order to study the anchoring instability mechanism of surrounding rock in deep roadway, the failure mechanism of the bolt‐anchoring agent interface was studied by simulating different strength rock mass and ground temperature environment, using C20, C40, and C60 strength concrete and steel pipe to simulate different surrounding rock strength environments. Indoor pull‐out tests were carried out to study the pull‐out load displacement relationship, ultimate pull‐out force, residual anchoring force, the distribution law of axial stress and tangential stress along the bar, and the energy consumption value of drawing failure at 20, 50, and 70°C. The test results show that, with the decrease of surrounding rock strength or the increase of ambient temperature, the pull‐out force, residual anchoring force, and energy consumption value of anchorage interface gradually decrease; under different axial forces, the axial force distribution of the rod body decreases exponentially from the anchoring end to the opposite end; and the shear stress transfers to the deep part of the anchor body with the increase of the load. According to the failure phenomenon of the specimen, the failure modes of the bolt bolt‐anchorage agent interface can be divided into shear slip mode and shear expansion slip mode. The shear expansion slip formula of anchorage interface is derived. Using high‐strength and temperature‐resistant resin anchoring agent for comparative test, the rationality of the mechanism analysis is proved, which provides more clear guidance for the construction of anchor support.

Research on Deformation and Failure Evolution of Deep Rock Burst Drivage Roadway Surrounding Rock under Dynamic Disturbance

In order to explore the deformation and failure evolution characteristics of the surrounding rock during the connection process of the deep rock burst drivage roadway under the dynamic load disturbance, and based on this, the catastrophe mechanism of the roadway is analyzed, taking the rock burst accident of Longyun Coal Industry in Shandong Province on October 20, 2018, as the engineering background. FLAC3D was used to study the distribution evolution law of displacement, plastic zone, and stress field in the whole process of “Roadway Drivage‐Deformation and Failure‐Instability and Disaster” in the surrounding rock of deep roadway. The research results show that under the conditions of high stress and dynamic load disturbance, the surrounding rock deformation and failure are significant during the connection of the thick‐top‐coal roadway in deep, the roof is the most, the two ribs are the second, and the roadway top‐coal is in an “inverted trapezoid” sag pattern. When the length of the bolts is limited or the anchoring force of the cables is not enough to effectively restrain the roof, the impact of dynamic disturbance on the plastic damage of the roof is greater than that of the two ribs and the floor, and the plastic damage of the coal seam roof affecting the surrounding rock deformation of the roadway drivage played a leading role.

Contributory Factors and Distribution Characteristics of Asymmetric Deformation in Deep Tunnel

Aiming at the asymmetric deformation of the surrounding rock in deep tunnels, from the perspective of the mechanical environment of the rock layer, the physical characteristics of the surrounding rock and the geometric characteristics of the tunnel, five kinds of influencing factors for the asymmetric deformation of the tunnel surrounding rock were selected, and the change levels of various factors were established. Through orthogonal test methods, 25 sets of orthogonal test simulation schemes were designed to study the asymmetric deformation law of the surrounding rock of deep roadway under the combined action of various factors. Three surface displacements of the surrounding rock are used as indicators to weigh the influence of various factors on the asymmetric deformation of the surrounding rock. Through the Extreme Difference analysis and F Statistics comparison of the indicators, the dominant influencing factors affect the deformation of the surrounding rock are obtained. By studying the distribution of the maximum deformation position of the surrounding rock, we have obtained the asymmetry characteristics of the surrounding rock deformation. In addition, the simplified mechanical analysis of the key influencing factors of the deformation of the surrounding rock is given, and the distribution law of the asymmetric characteristics of the surrounding rock deformation is summarized. The above research can provide a certain theoretical reference for the asymmetric deformation control and supporting scheme design of the surrounding rock in deep roadway.

Deformation and failure characteristics of anchorage structure of surrounding rock in deep roadway

This paper investigated the stress evolution, displacement field, local deformation and its overall distribution, and failure characteristics of the anchorage structure of surrounding rock with different rockbolt spacing through the model experiments. The influences of the pre-tightening force and spacing of rockbolt on the support strength of the anchorage structure of surrounding rock were analyzed by the simulation using FLAC3D numerical software. The support scheme of the excavated roadway was then designed, and the effectiveness of this support scheme was further verified by the displacement measurement of the roadway. The results showed that the maximum displacement between the roof and floor of the west wing track roadway in Kouzidong coal mine, China is about 42 mm, and the maximum displacement between its both sides is about 72 mm, indicating that the support scheme proposed in this study can ensure the stability and safety of the excavated roadway.

Research on large deformation mechanism of deep roadway with dynamic pressure

AbstractIn this paper, the large deformation mechanism of deep dynamic pressure roadway is studied from the perspective of the formation and development of plastic zone, and creep and damage of rock mass. The results show that (a) the butterfly‐shaped plastic zone is a nonstable plastic zone, and its unique stress sensitivity and rock formation difference are important causes of disasters such as large deformation of deep roadway. (b) Established a creep model of anchored surrounding rock. Due to the existence of rock mass damage and creep, the range of the plastic zone of the surrounding rock is always dynamic. (c) Explain the mechanism of large deformation of surrounding rock in deep roadway. The source of large deformation of deep dynamic roadway lies in the formation of unstable plastic duct‐shaped zone, and the interference of external factors such as tectonic stress and mining disturbance is the main way to change the plastic zone from stable to unsteady. In addition, the increase in rock mass damage and creep promotes the continuous development of the plastic zone, which eventually leads to the large deformation of the surrounding rock of the roadway. (d) Guided by the deformation mechanism of the surrounding rock in the deep dynamic pressure roadway, the corresponding roadway support technology was proposed for the test roadway, and the better support effect was obtained through the test.

Mechanism and application of concrete-filled steel tubular support in deep and high stress roadway

The concrete-filled steel tubular (CFST) support has been proposed as a new passive support form for controlling the stability of surrounding rock in deep roadway. To explore the mechanism of CFST support in deep roadway, the mechanical performances of U-steel support and CFST support were compared by theoretical calculation and numerical simulation with the engineering background of 11031 ventilation roadway in Pingmei coal mine. Then, the section shape of CFST was optimized and the special-shaped CFST support was put forward. The special-shaped CFST support was applied to 11031 ventilation roadway of U36-steel support failed to control. The results indicate that: The ultimate bearing capacity of CFST support is much greater than that of U-steel support. The CFST support can provide great supporting force to the roof-floor and two sides of roadway. It can be applied to the roadway with large horizontal stress. The section bending modulus and ultimate bearing capacity of the special-shaped CFST support are greater than those of the circular CFST support. The displacements of 11031 ventilation roadway supported by the special-shaped CFST support was not great. So, the special-shaped CFST support can effectively control the surrounding rock in 11303 ventilation roadway.

Study on Micro-expansive Concrete-Filled Steel Tube Support for Controlling the Stability of Surrounding Rock in Deep Roadway

The overall supporting capacity of ordinary concrete-filled steel tube support (CFSTS) can be decreased due to the self-shrinkage of concrete and the cracks of hardened concrete. The micro-expansive CFSTS is put forward in this paper. Firstly, the optimum proportion of micro-expansion concrete was determined by concrete strength testing. Then, the deformation of micro-expansion CFSTS and ordinary CFSTS under the same load w studied by numerical simulation. Finally, the micro-expansion CFSTS and ordinary CFSTS were applied to the roadway respectively. The results show: The expansive agent content and water reducer content is 11 and 0.5% in the optimum proportion of micro-expansive concrete, respectively. Under the same load, the deformation of the ordinary CFSTS was much larger than that of the micro-expansion CFSTS. The deformations of roof–floor and two sides of roadway supported by the micro-expansion CFSTS were obviously smaller than that of roadway supported by the ordinary CFSTS. The micro-expansion CFSTS has stronger supporting capacity than ordinary CFSTS.

Study on strength softening of surrounding rock in deep roadway at Daqiang coal mine

Study on strength softening of surrounding rock in deep roadway at Daqiang coal mine

Elastic-Plastic Analysis of Surrounding Rock in Deep Roadway Considering Shear Dilatancy Property under Non-Uniform Stress Field

Elastic-Plastic Analysis of Surrounding Rock in Deep Roadway Considering Shear Dilatancy Property under Non-Uniform Stress Field

Research and Exploration on Combined Support Technology in Deep Soft-Rock Roadway

Because of the existence of high stress in the surrounding rock of deep roadway, the physical and mechanical properties of the surrounding rock to change, and the surrounding rock stress distribution is very different from the shallow, so the way of shallow roadway support is not suitable for deep roadway. Deep soft-rock roadway support is a complex systems engineering, it should consider the different geological conditions, roadway scope of application, construction technology conditions, construction period and the cost and other factors to determine the optimal combined support program, if the special geological conditions encountered in the construction, it should be timely to improve the supporting program to meet the construction safety and ensure the quality. This paper is based on the characteristics of deep roadway support, sums up the combined support form in the project, researches and analyzes the combined support technology, and explores how to use suitable combined support form in deep roadway.

Numerical analysis on stability of surrounding rock mass around deep roadway

Numerical simulations of the deep roadway were carried out through application of the strain-softening constitutive model. Differences between the deep and shallow roadway of the rock bearing structure were analyzed. Influences of the supporting resistance on the rock bearing structure at the deep roadway were discussed. The results show that there is alternation of strong and weak strength-softening region in the surrounding rock of deep roadway. However, the increase in the supporting resistance cuts down the size of strength-softening region of surrounding rock, decreases its strength-softening degree, and improves the stress distribution condition of the surrounding rock mass. It is concluded that the supporting resistance can raise the self-supporting ability of surrounding rock through controlling its strength-softening so as to make the rock bearing structure of deep roadway stable.

Surrounding Rock Classification in Deep Roadway of Coal Mine

With the increase of mining depth，most coals in China have been deep mining stage. Compared to the shallow roadway, the characteristics of deformation-failure of surrounding rock show significant differences in the deep roadway, and the deep rock features of the surrounding rock are not considered in the traditional classification of roadway. So it is needed that systematical study on the surrounding rock classification for the stability evaluation of the deep roadway to meet the demand of the support design and the construction of the deep roadway in coal mine of China. The paper puts forward classification system of surrounding rock in deep roadway of coal mine according to on-the-spot geological investigation, rock ultrasonic testing, in-situ ground stress testing and comprehensive analysis on the surrounding rock stability of deep roadway in typical ore area.