Rock Movement Research Articles

Differences in the Effectiveness of Pelvic Rocking and Rebozo Movements in the Lowering of the Fetal Head during First Stage of Maternity at the Clinic in Kwala Bekala Village

Background: The natural process of delivering or expelling the fetus and placenta is a spontaneous and physiological event. Despite the inherent pain experienced by the mother and the extended duration of complete opening, some opt for alternative interventions, such as cesarean sections. Additionally, pharmacological drugs may be administered to facilitate the timely expulsion of the fetus and placenta. Aim: The purpose of this study was to analyze the effectiveness of pelvic rocking and rebozo movements in lowering the fetal head in women in the first stage of labor. Methods: This study used a quantitative analytic method with a quasi-experimental research design with a two-group comparison of pretest-posttest design. Results: The results of the study showed that before and after the pelvic rocking movement was carried out, the asymptote sig value was obtained. The 2-tailed was found to be 0.000 less than the alpha level of 5% (0.05), so it can be concluded that there is a significant difference in decreasing the fetal head. An asymptote sig value was found for the rebozo movement. The fetal head's descent varied significantly before and after the rebozo movement, as shown by the 2-tailed statistic's finding that it was 0.003 less than the 5% alpha threshold (0.05). Conclusion: The conclusion of this study was that the significance value of pelvic rocking was 0.000, which was smaller than the rebozo significance value of 0.003, which means that the pelvic rocking group was more effective in decreasing the fetal head compared to the rebozo group. So, it is very useful if the pelvic rocking movement service is carried out when passing through the first stage of labour.

ОГЛЯД СУЧАСНИХ УЯВЛЕНЬ ПРО ДИНАМІКУ ДЕФОРМУВАННЯ ВУГЛЕПОРОДНОЇ ТОВЩІ НАД ВИРОБЛЕНИМ ПРОСТОРОМ ЛАВ

Purpose. Analysis of modern studies of the processes of deformation of rock strata in the undermine zone during the development of coal seams in order to determine the general features and views that allow to substantiate the mechanistic model of deformations and subsidence. Methods. The work uses the method of engineering analysis, synthesis and generalization of information from various literary sources. Findings. Retrospective analysis of scientific studies devoted to the consequences of underground mining of stratum minerals by longwalls allowed to determine the main components of the process of deformation and movement of rocks in the undermine zone. Based on the conducted analysis, it was concluded that in the process of subsidence in the rock strata during the excavation of coal seams with the roof collapse method, different scientists distinguish from three to nine zones. The main three zones, which are components of all existing hypotheses today, are: the collapse zone, the zone of complete displacements, the zone of destruction. Based on the formation of these three zones, it is advisable to develop a schematic diagram of models for prognostic research. Originality consists in establishing the general mechanism of deformation and movement of the rock strata in the zone of longwall undermine. Practical implication. The research results can be used in the selection and justification of the mechanistic model, which is the basis of the calculation scheme during mathematical modeling. This will allow to provide high-quality results of forecasting subsidence of the earth's surface by longwall mining, as well as to adequately assess the effectiveness of measures to protect surface infrastructure objects. Keywords: earth's surface displacement, surface undermine, landslides, displacement trough, surface displacement forecast.

ЗІСТАВЛЕННЯ ДЕФОРМАЦІЙНИХ ВЛАСТИВОСТЕЙ ОХОРОННИХ СПОРУД ПІДГОТОВЧИХ ГІРНИЧИХ ВИРОБОК

Purpose. Investigate and compare the deformation properties of protective structures in the form of coal pillars and structures made of crushed rock for a justified choice of the protection method, which can make it possible to ensure the stability of side rocks in the coal massif and preparatory works in the mining areas in the coal mine. Methodology. To achieve the goal, laboratory studies were performed on experimental samples subjected to uniaxial compression. For pillars, their thickness was changed, whereas for structures made of crushed rock the thickness of the rock layer was changed at a constant cross-sectional area. Results. As a result of the conducted research, the deformation properties of protective structures that were subjected to uniaxial compression have been determined. A 15% reduction in their stiffness was recorded for pillars, when their thickness h0 was two times changed, and for the external static load, which varied according to a linear dependence. Within the limits of the safe deformation resource, when the relative deformation is in the range of values 0.18≤λ≤0.23, the stability of the pillars and their bearing capacity is ensured. At the same time, the relative change in their volume should not exceed 7-9%. It has been established that exceeding the limit level of the specific potential energy of deformation by an average of 12-14% causes the destruction of coal pillars. For protective structures made of crushed rock with a relative volume change of 0.35≤δV≤0.28, the value of the compaction coefficient of the original material decreases from kcons = 1.5 to kcons = 1.42 with a simultaneous increase in the work of compression and an increase of more than 20% in the specific potential energy of deformation, thanks to which the rigidity of the embedded material and the bearing capacity of protective structures made of crushed rock are ensured. Scientific novelty. The regularities of formation of deformation properties of protective structures under conditions of uniaxial compression, taking into account the change in the specific potential energy of deformation and the relative change in their volume, have been established. Practical significance. In order to ensure the stability of side rocks in the coal massif and preparatory workings at excavation sites in the coal mine, the feasibility of using partial or complete paving of the produced space from crushed rock, which limits the movement of side rocks in the produced space, has been substantiated.

STUDY OF DEFORMATION PROPERTIES OF PROTECTIVE STRUCTURES OF PREPARATORY MINING WORKS

Purpose. To study the stability of the security structures of the preparatory mine roadways of steep seams while unloading the coal-rock massif to prevent the collapse of side rocks in the excavation areas of the coal mine and create safe working conditions for miners. Method. In order to achieve the aim of the research, the study of the stability of security structures was carried out at the laboratory of mountain pressure by using experimental samples in the form of whole coal and structures consisted of crushed rock, which were subjected to uniaxial compression. Results. Under the conditions of uniaxial compression of whole coal or constructions consisted of crushed rock, with the ratio of length to width a/b= (1-2) and an increase in the cross-sectional area S (m2) of the experimental samples, a relative change of their volume δV was observed. For whole coal, the steady state is ensured by the relative volume change δV ≤ 0,1. Beyond the set value of δV, the whole coals lose their stability and collapse, which results in the collapse of the side rocks. For the crushed rock structures, with an increase in the cross-sectional area of the compressible specimens, the relative volume change decreases from δV = 0,2 to δV = 0,35. At the same time, the crushed rock is compacted in the whole volume of the used material, the bearing capacity of protective structures is increased, which enables limiting the movement of lateral rocks and ensures their integrity. Scientific novelty Within the limits of the deformation resource of protective structures consisting of crushed rock of different granulometric composition, with their uniaxial compression, a type of functional dependence was established, which enables us to estimate the relative change in the volume of flexible supports from stiffness, which is necessary for assessing their bearing capacity. Practical significance. In order to create safe working conditions for miners in the excavation areas of a deep coal mine and prevent the collapse of side rocks in the coal massif, it is advisable to use flexible protective structures for the protection of preparatory coal mine roadways, when the ratio of their linear dimensions corresponds to the ratio of length to width of a/b>(1-2).

ИССЛЕДОВАНИЯ ПО ОЦЕНКЕ СОВРЕМЕННОЙ ГЕОДИНАМИЧЕСКОЙ АКТИВНОСТИ ПРИ ПОМОЩИ МЕТОДИКИ СРЕДИННОГО ГРА ДИЕНТА

The article presents the results of studying the possibility of joint application of one of the techniques of electrical exploration and geodetic monitoring for geodynamic assessment of the stress-strain state of the massif from the surface. Modern geodynamic activity indirectly affects the change in the values of apparent electrical resistivity of the array, as the movement of rocks leads to changes in the volume of pores and cracks, which are often filled with aqueous solutions. In addition, the distribution of electrical properties of rocks in the near-surface part of the section is influenced by meteorological conditions. At the same time, the influence of meteorological conditions on the section is distributed uniformly, and in order to exclude the influence of their change between observation series, it is proposed to use normalization of measured values of apparent resistivity of rocks. The results obtained are a prerequisite for the continuation of research on the use of the median gradient methodology in the complex of geodynamic diagnostics.

Research on Movement Monitoring and Law of Overlying Strata in Goaf Based on IMU Technology

The overlying strata of the stope can be divided into low ( immediate roof ), medium and high strata according to the degree of influence of the mine pressure behavior of the working face. Among them, the pressure step distance of low rock strata can be judged according to the roof pressure appearance of hydraulic support, and the middle and high rock strata can not be accurately and intuitively determined only by theoretical calculation. Therefore, IMU is used to monitor the motion state and fracture distance of different layers, so as to study the relationship between them and periodic weighting. Firstly, the accuracy of monitoring effect and the error of monitoring data are determined by indoor test. Then, taking the 52507 working face of Daliuta as the engineering background, 3DEC software is used to assist the verification. The research shows that the IMU monitoring data meets the requirements of error and accuracy, and can accurately monitor the rock movement ; the movement period of rock strata at different heights is different. As the height of rock strata increases, the displacement distance of rock strata gradually increases, and the median rock strata play a key role in the movement of overlying rock strata. The periodic pressure monitored is twice the actual periodic pressure.

Raw Gangue Filling Mining under Construction <br/>—A Case Study in China

In order to recover the strip pillar coal resources, reduce the amount of gangue mountain and realize remediation of the goaf environment in the old mining area, the raw gangue filling mining technology was proposed. According to the previous practical experience, the feasibility of the implementation of raw gangue filling mining technology in the coal-pressed area was analyzed. Through the filling gangue compaction test, the deformation under different loading stages was obtained. Further, a reasonable prediction of the deformation beyond the experimental limited loading load was made based on the experimental results. Through the deformation source analysis of the whole process of gangue filling, the key factors for controlling deformation before, during, and after filling were determined. Additionally, the proportion of deformation during different stages was quantified. Considering the protection of surface buildings, mining fullness of the working face and mining technology, the production parameters of 1209 and 1210 filling working faces were preliminarily determined. Through numerical simulation, the rationality of mining scheme was verified. Based on the practice of 1209 working face and the key factors to control the deformation of gangue filling, the mining system and process in 1210 working face were optimized. According to the measured surface rock movement, raw gangue filling mining technology can meet the requirements of surface building protection level. Especially, this paper provides a method to quantitatively calculate the equivalent mining height (EMH) of raw gangue filling and its mining deformation, which has reference significance for old mining areas.

WALL STABILIZATION IN MINES BY SPRAY-ON LINERS

AbstractThin spray-on liners (TSLs) have been found to be effective for structurally supporting the walls of mining tunnels and thus reducing the occurrence of rock bursts, an effect primarily due to the penetration of cracks by the liner. Surface tension effects are thus important. However, TSLs are also used to simply stabilize rock surfaces, for example, to prevent rock fall, and in this context crack penetration is desirable but not necessary, and the tensile and shearing strength and adhesive properties of the liner determine its effectiveness. We examine the effectiveness of nonpenetrating TSLs in a global lined tunnel and in a local rock support context. In the tunnel context, we examine the effect of the liner on the stress distribution in a tunnel subjected to a geological or mining event. We show that the liner has little effect on stresses in the surrounding rock and that tensile stresses in the rock surface are transmitted across the liner, so that failure is likely to be due to liner rupture or detachment from the surface. In the local rock support context, loose rock movements are shown to be better achieved using a liner with small Young’s modulus, but high rupture strength.

EXPERIMENTAL STUDIES OF THE STABILITY OF HAULAGE DRIFTS ON PITCHING SEAMS WITH DIFFERENT METHODS OF PROTECTION

Purpose: Study of the stability of haulage drifts on pitching seams with different protection methods in order to assess their operational condition and create safe working conditions at excavation sites in deep coal mines. Methodology: The research used a comprehensive approach, including research analysis of the problem under study, field experiment and data processing. Conclusions: As a result of the conducted research, it was established that when protecting the haulage drifts on pitching seams of solids of coal, in the area of influence of cleaning works, the cross-sectional area of the preparatory work decreases by 50 % or more, and the deformation of protective structures after losing their stability reaches the maximum value λ = 0.8. At the same time, the fastening in the product is deformed, and the side rocks collapse. The industrial situation provokes injuries from collapses. When protecting the roll-back stretch with wooden piles, after their compression (when the relative deformation reaches the maximum values of λ = 0.6), the loss of the cross-sectional area is about 30 %, and the bearing capacity of the protective structures allows you to limit the movement of side rocks and prevent their collapse. Implications of research: In order to create safe working conditions for miners in preparatory workings in mines with steep coal beds, it is recommended to use flexible protective structures that limit the movement of side rocks in the mined space. Originality: A functional dependence in the form of a time series was established, which takes into account the change in the relative deformation of protective structures during the operation of the production at the excavation site.

Optimization of Physical Parameters and Analysis of Rock Movement and Deformation Patterns in Deep Strip Mining

China’s shallow coal resources are gradually diminishing, and deep coal resources have slowly become the main energy source. However, the destruction mechanism and evolution of deep rock formation structure are not clear, which seriously restricts the exploitation and utilization of deep energy. Here, the optimization of the physical parameters and the deformation law of the overlying rock in a deep mine in Shandong Province were studied with an integrated approach including similar simulation, mechanical analysis, numerical simulation, and measurement verification, etc. First, the paper simplified the rock formation and developed a numerical model using the field exploration data; second, we analyzed the mechanical properties of each rock formation, obtaining the key rock formation that affects the surface deformation of the mining area. Furthermore, we tested the physical parameters of rock formation by using the orthogonal test, optimizing the physical parameters of rock formation with the extreme difference, and variance analysis of the orthogonal test results. Then, using FLAC3D, we conducted numerical calculations for strip mining of deep wells with numerous working faces, analyzing the maximum surface subsidence value, the maximum horizontal movement value of ground surface at different mining depths, and the change in the subsidence coefficient. By analyzing the linkage relationship between the surface phenomenon and deep mining, we obtained the optimal mathematical model of the three and the coal seam mining depth, which revealed the linkage law of “deep formation–earth surface”. Finally, the model relationships of the influence boundary value, maximum subsidence value, maximum horizontal movement value, and mining depth for each rock layer were separately established.

Research on the Overburden Movement Law of Thick Coal Seam Without-Support Gangue-Filling Mining

Filling mining technology is a feasible and effective means to build a green mine and protect the environment. In order to investigate the overlying rock movement law of gangue-filling mining under the condition of no support for thick coal seams, this paper takes the Sima mine as the research object and determines the relevant parameters of rock mechanics in the mine area through a uniaxial compression test, a uniaxial tensile test, and a uniaxial shear test, which lay the foundation for the numerical simulation and similar simulation experiments. The optimal solution was determined by the numerical simulation, the effects of mining width and mining sequence on the overlying rock stress and deformation were analyzed, and the accuracy of the results was further confirmed by combining with similar simulation experiments. The results show that the mining sequence of jump mining with large intervals adopted in this paper can make the backfill solidify fully and is more conducive to the working face support and roof management. The larger the mining width, the larger the deformation of the overlying rock seam and the surface. It shows that the smaller the mining width, the smaller the increase of stress caused by excavation and filling, which is more favorable to the stability of the coal column and filling body. This paper deals with coal mine solid waste, while realizing the effective control of surface subsidence and providing a theoretical basis for the construction of green mines.

Failure Process Analysis of Landslide Triggered by Rainfall at Volcanic Area: Fangshan Landslide Case Study

The Fangshan landslide was a rainfall-induced landslide that occurred in a volcanic area in the Fangshan scenic spot, Nanjing, Jiangsu, China. On 25 October 2016, after approximately 10 days of continuous rainfall, a shallow landslide rapidly developed, which triggered slow movement of deep mudstone rock. According to the characteristics of the landslide body, measures such as anti-slide piles, anchor cables and drainage were used to reinforce the landslide. Active drainage measures included arranging plant growth zones at the trailing edge of the landslide, and passive drainage measures included arranging pumping wells at the trailing edge of the landslide. It is worth emphasizing that the Fangshan landslide was the first example of a landslide in Jiangsu Province, China that was treated by actively lowering the water pressure. After landslide treatment from 16 May 2017 to 21 January 2018, the Fangshan landslide tended to be stable. However, the stable landslide was reactivated by the rise in groundwater level caused by rainfall and pumping well damage and underwent accelerated downward sliding in July 2020. The Fangshan landslide has caused great damage to the roads and buildings of Fangshan scenic spot, with a direct loss of RMB 6 million and an indirect loss of RMB 95 million. This article discusses the development process of the shallow soil landslide and the underlying deep mudstone rock landslide. The influence of groundwater level variation on the deformation of the shallow soil landslide and deep mudstone rock landslide of the Fangshan landslide are also discussed.

Potential triggers for large earthquakes in open‐pit mines: A case study from Kuzbass, Siberia

AbstractThe extraction and movement of rock during mining operations is considered a possible trigger for slip along the fault. In this study, possible anthropogenic causes were analyzed for triggering the earthquake with the local magnitude of ML = 6.1 (at a depth of 4 km just beneath the quarry), in the vicinity of the large coal open‐pit mine in Russia. This event was the largest earthquake associated with a quarry (an open pit). A sufficiently deep occurrence of the source testified that seismic vibrations were produced in a dynamic slip along a preexisting and prestressed tectonic fault. Analytical calculations were conducted of increments of normal and shear stresses at fault planes with several dip angles at depths corresponding to the probable location of the hypocenter of the Bachat earthquake. As the results show, long‐term rock excavations bring a prestressed thrust fault closer to the ultimate Coulomb strength, and stress variations at those depths may suffice to initiate a movement along the fault. By measuring seismic vibrations at different quarries and mines in Russia, the dynamic effect at the supposed depth of the source occurrence could be reliably estimated. As is shown, the ultimate anticipated dynamic deformations are noticeably lower than corresponding values produced by seismic waves of distant earthquakes in the case when the effects of dynamic triggering were observed. Accordingly, the seismic effect of explosions cannot trigger a large earthquake with deep source occurrence. Operations in open‐pit mines can only bring forward the moment of an earthquake at a potentially seismogenic fault. At the same time, the numerical calculations reveal that a branching network of underground tunnels located at several horizons can noticeably reduce the effective shear modulus of the host rock. This effect can even provoke a dynamic movement at a previously aseismic fault.

МОДЕЛИРОВАНИЕ ГЕОМЕХАНИЧЕСКОГО СОСТОЯНИЯ ПОРОДНОГО МАССИВА ПРИ ОТРАБОТКЕ ПОДЗЕМНОГО ПРОСТРАНСТВА БОЛЬШИМИ ПЛОЩАДЯМИ

The article considers the mechanical and mathematical modeling of the process of subsidence of the Earth’s surface during the mining of rock mass by a pillar mining system. The task is to study the influence of the waste space on the state of the rock strata located at different depths (Horizons) at each stage of the process of rock movement. The purpose of the study is to develop a numerical geomechanical model of a rock mass using a pillar mining system, which makes it possible to correctly identify the characteristic zones formed as a result of mining operations in the rock column, and also provides an opportunity to simulate the process of formation of the daily surface subsidence trough. Computational numerical schemes of model problems are constructed using finite element and discrete element modeling algorithms. Based on the results of numerical modeling, it is shown that the characteristics (linear dimensions and maximum subsidence) of the subsidence trough obtained in accordance with the developed geomechanical model are close to the characteristics calculated by the engineering methodology used in the conditions of the Starobin potassium salt deposit (Republic of Belarus). At the same time, as the depths of mining operations increase, the discrepancies between them increase. The analysis of the reasons for this behavior is carried out. The nonlinear nature of the change in the boundary angles of displacement in the layers of the rock strata with an increase in the depths of mining is presented and conclusions explaining these changes are noted. The application of the obtained modeling results is to substantiate the possibility of reducing the size of the security pillars around the mine shafts and ground objects with an increase in the depths of mining operations, thereby reducing the amount of mineral reserves left in the bowels and increasing the economic indicators of extraction.

Evaluation of the performance of yielding rockbolts during rockbursts using numerical modeling method

The assessment of yielding rockbolt performance during rockbursts with actual seismic loading is essential for rockburst supporting designs. In this paper, two types of yielding rockbolts (D-bolt and Roofex) and the fully resin-grouted rebar bolt are modeled via the “rockbolt” element in universal distinct element code (UDEC) after an exact calibration procedure. A two-dimensional (2D) model of a deep tunnel is built to fully evaluate the performance (e.g., capacity of energy-absorption and control of rock damage) of yielding and traditional rockbolts based on the simulated rockbursts. The influence of different rockburst magnitudes is also studied. The results suggest that the D-bolt can effectively control and mitigate rockburst damage during a weak rockburst because of its high strength and deformation capacity. The Roofex is too “soft” or “smooth” to limit the movement of ejected rocks and restrain the large deformation, although it has an excellent deformation capacity. The resin-grouted rebar bolt can maintain a high axial force level during rockbursts but is easy to break during dynamic shocks, which fails to control rapid rock bulking or ejection. Three types of rockbolts cannot control the large deformation and mitigate rockburst damage effectively during violent rockbursts. The rockburst damage severity can be significantly reduced by additional support with cable bolts. This study highlights the effectiveness of numerical modeling methods in assessing the complex performance of yielding rockbolts during rockbursts, which can provide some references to improve and optimize the design of rock supporting in burst-prone grounds.

Justification of underfill in mined-out voids in cut-and-fill stoping

The paper considers the issue of assessing the proportion of unfilled voids in ore mining by the cut-and-fill method with cemented paste backfill. The efficiency of such mining systems is directly related to the proportion of backfill in the mined-out voids. The underfill of such voids may lead to negative processes in undermining, such as rock movements, dynamic events induced by rock pressure and growth of water-conducting fractures. The mined-out void fill factor is the coefficient A which is the ratio of the backfill volume to the void volume. According to standards, it should not be less than 0.98. Such value of the coefficient governs an unacceptable underfill sometimes. The paper substantiates the maximum underfill with regard to the recently predominant transition to the cut-and-fill mining method, as well as the causes of the increasing underfill, such as the uncontrolled roof failures. Based on the statistical processing of in-situ data, it is shown that the proportion of the neglected underfill can reach 0.13% under the most  unfavorable conditions, which is lower than the rated value of the allowable underfill and isincapable to lead to a significant change in the nature of rock movements. The calculated values of the mined-out void fill factor are 0.995–0.998 at the mineable ore body thickness of 20–50 m. Thus, in the modern conditions of copper–nickel ore mining, particularly at Talnakh, the fill factors in the cut-and-fill stoping practice need to be adjusted. The fill factors obtained in this study can be used for the more reasonable calculations when solving issues related to rock mass movements, which, among other things, can have a positive influence on the cost of protection of undermined objects.The authors appreciate participation of members of Norilsk Nickel’s Polar Division Yu. N. Nagovitsin, M. P. Sergunin, A. A. Kisel, A. A. Bazin and A. K. Ustinov in this study.

Monitoring of ground surface deformation at Taimyrsky Mine using Sentinel-1 radar imaging for geodynamic risk assessment

The modern stage of mineral mining involves prediction of geotechnical risks. One of the major methods in this regard is the geodynamic zoning. The key target is to assess the cross-effect of mining operations and blocks structure of the Earth’s crust. This article presents the information on ground surface subsidence within the boundary of the mining lease of Taimyrsky Mine as a result of processing of paired images from Sentinel-1A sate llite. The implemented probabilistic kinematic analysis revealed some features of movements in overlying rock mass, in particular, local uplifts of ground surface. The detailed information on vertical deformations was obtained. Such approach enabled detecting the deformation areas subjected to the effect of the global tectonics which is, as a rule, neglected in geotechnical risk assessment while it directly affects mining safety. Despite the apparently consistent patterns resulted from processing of satellite images, the method InSAR is only used as a supplemental technique since the relevant regulatory framework is yet absent. In combination with the conventional surveying for monitoring ground surface deformations, the method InSAR enhances efficiency of monitoring and improves accuracy of geodynamic risk prediction in the course of mineral mining, inclusive of observations over the global tectonic processes. The probabilistic kinematic analysis allows for getting insight into the mechanism of overlying rock mass movement with regard to rock mass jointing and, jointly with InSAR, can be used in the artificial intelligence systems for learning models of prediction of overlying rock movement parameters during mineral mining.

Classification of the Zubair Subzone oilfields using structural contour maps, Southern Iraq

Zubair subzone is the southernmost unit of the Mesopotamian zone of Iraq and the most oil-producing region in Iraq. Rumaila, Zubair, Ratawi, Tuba, Nahr Umr, Majnoon, Luhais, Subba, Sanam, and Siba are subsurface structures that form the oilfields in the Zubair subzone. Seismic and well-log data were collected from different sources and used to conduct the geometric and genetic analyses of these structures at the top of the Mishrif Formation. The results show that there are two types of structures; these are anticlines and salt structures. The anticlines can be classified geometrically into linear, brachy, and culmination. The most prominent linear anticlines are Rumaila and Zubair, which are long and relatively narrow anticlines with an N–S trend separated by broader synclines. Each one of these two anticlines consists of two domes separated by a saddle. Brachy anticlines include Tuba, Luhais, and Subba. Ratawi is the only culmination fold in the area. The salt structures are Nahr Umr, Majnoon, Sanam, and Siba. The structures of the Zubair subzone have formed as a result of the Alpine orogeny of the collision between the Arabian and Eurasian plates, the salt tectonics of the Infracambrian Hormuz Formation, and the movements of basement rocks. All these factors have controlled forming the subsurface structures. The anticlines are affected mostly by the Alpine orogeny and the basement faults, while the salt structures are affected mostly by the salt tectonics. Three major basement faults with NE-SW trend control the distribution of saddles and plunging areas of the subsurface structures. Other shorter faults with the N–S trend, which are parallel to the hinge lines of the anticlines, control the asymmetry of the anticlines, especially Rumaila and Zubair.

Study on the Instability Activation Mechanism and Deformation Law of Surrounding Rock Affected by Water Immersion in Goafs

Large-scale goafs are left after coal seam mining. Due to the low-lying terrain, the goaf will be filled and soaked by groundwater, which may lead to instability of the remaining coal pillars in the goaf and cause uneven settlement of the overlying rock. Consequently, there may be overlying rock movement and surface subsidence, which endangers the safety of the building (structure) above the goaf. Considering the strip goaf of Dai Zhuang coal pillar as an example, this study investigated the evolution of instability and deformation of surrounding rocks affected by water immersion using the similar material simulation test method. The results of the study reveal that under the effect of prolonged water immersion in the goaf, the damage to the coal pillar in the strip underwent a stagewise evolution process of several instances of creep damage at the edge of coal pillar followed by overall destabilization damage, and the overburden movement revealed stage characteristics of small step subsidence several times followed by sudden large subsidence. Furthermore, based on Wilson’s coal pillar instability theory, the instability mechanism of the strip coal pillar under the action of water immersion was found to be triggered by the reduced strength of the coal pillar from the effect of water immersion, the continuous creep damage to the strip coal pillar from outside to inside, and the continuous shortening of the elastic zone of the coal pillar until its bearing capacity was lower than the load it was carrying. The research results are expected to serve as theoretical guidance for the study of coal pillar stability and the development and utilization of surface construction above goafs.

Optimization and Simulation of Monitoring Technology of Blasting Rock Movement Trajectory Based on the Improved SVM Algorithm

In most cases, the blasting object is the rock mass. Because the rock mass has the characteristics of anisotropy and inhomogeneity, there are often structural surfaces such as joints, fissures, faults, and weak interlayers, but details are basically impossible. Compared with the rock, these structural surfaces are weak parts, and the explosive energy required for breaking is smaller. It is difficult to take into account the existence of each weak side when the explosives are arranged in the blasthole. Therefore, after the explosive explodes in the rock mass, the explosive gas will first rush out from these weak parts, entraining individual fragments to form flying rocks. Aiming at the problem that it is difficult to accurately obtain the rock motion information in the blasting process of open-pit mines, this paper selects the kernel function to establish the support vector machine model and optimizes the parameters of the support vector machine model to obtain the optimal blasting rock trajectory prediction model. Under the protection of special protection devices, the information of the rock movement during the blasting process is collected at a higher frequency, and the analysis algorithm of the rock movement characteristics is researched on the basis of inertial navigation technology. The algorithm is used to analyze and output the rock movement. The curve of velocity, position, and kinetic energy provides a theoretical and technical basis for the study of rock movement law in the blasting process of open-pit mines. Through the experimental analysis, based on the cross-validation method, through the support vector machine model parameter optimization and comparison evaluation parameters, the optimal prediction model of the blasting rock trajectory is obtained as the support vector machine model based on the radial basis kernel function. The mean value of root mean square error and mean absolute error of this model are 0.102 and 0.0674, respectively, and the performance is the most robust among the three types of models.