Abstract:A new open-face tunnel boring machine(TBM)was applied in the Xi'anshan Inclined Shaft Project,and a"Squatting Beam Reaction Sliding Rail"TBM stepping process was designed based on the inclination of the starting inclined shaft,the geological conditions at the portal and the site.Based on the sliding track stepping method,two design focuses of the"double station beam kneeling coun-terforce sliding track stepping"were studied,including:the design principles and methods of the steel reinforced concrete expansion foundation for the starting guide platform;and the structural design of the station beam and kneeling beam.The conclusion drawn from this study is that the counterforce station beam and kneeling beam structure and the guide platform foundation design of the open-face TBM for iron ore inclined shaft can avoid the large friction caused by direct contact with concrete,and can effectively reduce the power demand for empty push stepping.The proposed double station beam kneeling counterforce stepping equipment design greatly simplifies the construction equipment.Note that the initial foundation height should be selected when calculating.The wall thickness design of the kneeling beam and station beam should be calculated based on the combination of the dimensions of the beam and the column.

Abstract:To address the challenge of sudden water inflow in the deep-buried tunnels of the Western Trunk Line of the Central Shanxi Yellow River Diversion Project,a surface-directed plugging drilling technique was adopted.The study analyzed the adaptability of drill hole design,drilling equipment se-lection,and drilling construction processes.By optimizing the borehole trajectory and implementing a structural design featuring three-stage borehole diameters and two-stage casing,combined with com-posite drilling techniques and a combination of air drilling and mud drilling,precise trajectory control and efficient drilling were achieved.Field test results indicate that the ground-based directional plug-ging boreholes for the deep-buried water-bearing tunnel on the West Trunk Line achieved a cumulative drilling length of 1 929.94 meters with a 100％success rate.All boreholes precisely penetrated the predetermined tunnel locations,laying the foundation for subsequent aggregate filling and grouting plugging operations.These research findings provide valuable reference for ground-based directional plugging borehole drilling construction under similar conditions.

Abstract:To study the deformation and damage characteristics of surrounding rock and develop safe and efficient support schemes for small TBM excavation in coal mine roadways,a φ2.5 m small TBM excavation gas drainage roadway in a coal mine in Huainan Zhangji Coal Mine mining area was taken as the engineering background.Based on the geological conditions at the construction site,a numerical model using the discrete element method was established to conduct numerical simulations.The study focused on the distribution and evolution of stress fields,displacement fields,and crack fields in the surrounding rock of the roadway under the disturbance caused by small TBM excavation,as well as the effectiveness of different support schemes.The results showed that after TBM excavation,the maximum displacement value occurred at the roof of the roadway,and the surrounding rock mainly exhibited shear cracks.The stress concentration at the top and bottom of the roadway was significantly higher than that at the sidewalls.The 1.8 m rockbolt performed better in controlling stress concentration,roadway deformation,and crack propagation in the surrounding rock,but its ap-plication on-site was inconvenient.On the other hand,the 1.5 m short rockbolt met the requirements for roadway support in terms of support strength and construction efficiency.

Abstract:Traditional creep models often fail to accurately describe the non-steady-state creep charac-teristics of rocks,especially the nonlinear behavior during the accelerating creep stage,which limits the applicability and precision of the models.To address this issue,this study replaces the traditional dashpot with a fractional-order dashpot based on the classical generalized Kelvin model and the Muray-ama body model.This leads to the proposal of an improved generalized Kelvin body and Murayama body model.Additionally,a new fractional-order creep model for rocks is introduced using the super-position principle.Based on this,creep equations under one-dimensional and three-dimensional stress states are derived.To verify the validity of the model,experiments were conducted on green schist,red sandstone,and sandstone.The results indicate that the fractional-order creep model offers signifi-cant advantages in describing rock creep behavior.Compared to the traditional Nishihara creep model,the fractional-order creep model provides a more precise fit to experimental data,especially in the nonlinear phase,where the fitting accuracy is significantly improved.This confirms the rationality and accuracy of the model.

Abstract:In order to solve the problems of difficult selection of design and calculation parameters of steel fiber reinforced concrete wall seat of deep and large frozen shafts,relevant research was carried out with the auxiliary shaft of Subuerga Coal Mine as the engineering background.The mechanical properties of steel fiber reinforced concrete and benchmark concrete show that the shear strength,splitting tensile strength and compressive strength of steel fiber reinforced concrete are increased by 22.64％～46.56％,32.45％～34.51％and 0.70％～1.65％,respectively.Referring to the current design code for concrete structures,the standard values and design values of the shear,compressive and tensile strength of CF60～CF80 steel fiber reinforced concrete are obtained.Based on the current design method of the overall bearing capacity of the borehole structure,an optimization method for the design of the wall seat is proposed.The results show that the method is not only feasible,but also the values of the relevant parameters are well documented,which makes the design and calculation of the steel fiber wall seat of the deep and large frozen wellbore more scientific and reasonable.

Abstract:Investigating the seepage behavior of grout in fractured rock masses and its ultimate restora-tion and reinforcement effects is essential for advancing grouting theory and optimizing engineering grouting parameter design.This study systematically examined the influence of ambient temperature and grouting pressure conditions on chemical grouting processes,designing and conducting a series of laboratory-scale simulation tests.Innovatively employing Low-Field Nuclear Magnetic Resonance(LF-NMR)technology,the tests achieved in-situ,non-destructive,real-time dynamic monitoring of the grout's seepage and diffusion processes within the fracture network of the rock mass.Through in-depth analysis of the T2 relaxation time distribution response characteristics obtained via LF-NMR,this research systematically revealed the specific influence patterns of temperature variations on grout rheological properties,effective grout diffusion range(grout intake volume),and macro-scale permea-bility of the rock mass.Concurrently,direct shear testing on grout-reinforced rock specimens cured under different temperature conditions quantitatively evaluated the critical role of temperature on the final mechanical properties of the grouted body.The results unequivocally demonstrate that tempera-ture is a key controlling factor for grout seepage behavior,with elevated temperatures causing signifi-cant reductions in rock mass permeability,thereby impeding effective grout diffusion;the mechanical performance of the grout-reinforced composite exhibits strong temperature dependency,with its shear strength parameters-angle of internal friction(φ)and cohesion(c)both displaying distinct expo-nential decay trends with increasing temperature.Building upon these core findings,this study further established and validated a mechanical model for the shear strength of the grout-rock interface capable of quantitatively characterizing temperature effects,explicitly incorporating the temperature-dependent evolution of key parameters.The research outcomes provide significant theoretical founda-tions and practical parameter design references for grouting engineering in complex environments such as deep-buried tunnels with high geothermal temperatures.

Abstract:To clarify the main influencing factors of the key processes of frozen drilling in the wellbore of the Taigemiao mining area,an analysis was conducted based on the distribution characteristics of the rock strata in the mining area and the physical and mechanical properties of various types of sand-stone,combined with the actual drilling construction data.Analysis suggests that the total thickness of sandy rock strata in the mining area accounts for more than 80％.The overall distribution of the rock strata is simple,with low compressive strength and small rock strata inclination.However,the rock strength varies greatly at 300 m and 650 m,and the alternating hardness of the rock is prone to cause borehole deviation.In a very few layers,there is a risk of slurry leakage and diameter reduction,which requires attention during the drilling period.Through the statistical analysis of the drilling effi-ciency of the four shafts in the mining area,it is concluded that the actual conditions of the strata are more favorable than the expected conditions,the drilling period is guaranteed,and the drilling effi-ciency of 2 100 m/(unit·month)can be achieved.

Abstract:Based on the strategic planning of the Second Curve and supported by the"Technology Inno-vation Provider"service model,this study constructs an implementation path of"Precise Scenario A-lignment-Technology Empowerment-Customized Solution Implementation"to promote the cross-in-dustry application of specialized shaft sinking technology from the coal sector to water network con-struction.By accurately identifying the needs for disaster-prone stratum treatment during water net-work development,this study drives the deep restructuring and targeted upgrading of the technology to ensure its full adaptation to the new scenarios.Through optimizing the innovation ecosystem,and conducting organizational restructuring,capital empowerment,synergistic resource allocation,and brand enhancement,this study has strengthened the support system for the Second Curve,breaking through the scale barriers of traditional business and facilitating the dynamic integration of"technology chain-industry chain-value chain."This achieves a synergistic mechanism between the First and Second Curves.Empirical results show that this approach drove a 93.83％year-on-year in-crease in newly signed contracts in 2025 compared to 2024,with the Second Curve accounting for 68.18％of the total annual contract value.These findings validate the foresight of the Second Curve strategy and the effectiveness of its implementation,providing a valuable reference for similar enter-prisesnavigating business cycles.

Abstract:In response to the issue of safety degradation in tunnel lining structures due to crack damage and the lack of an effective evaluation system,this study establishes a"load-structure"model using ABAQUS finite element software.It employs the extended finite element method(XFEM)to conduct discontinuous analysis.Through multi-condition simulations,the study investigates the effects of crack spatial distribution,morphological characteristics,and quantity variations on the mechanical be-havior of the lining.The results show that cracks at the crown of the tunnel have the most significant impact on the safety of the lining.An increase in crack depth leads to a substantial reduction in the safety factor of the section,while an increase in crack length and number further diminishes the safety factor.Based on the quantified analytical results,a multi-parameter evaluation method is developed u-sing fuzzy hierarchical analysis,providing a scientific basis and technical support for the risk assess-ment and maintenance decision-making of tunnel lining cracks.

Abstract:Taking the runway project of an international airport in the hilly region of southwestern Chi-na as an example,this study investigates the geotechnical and rock testing practices for airport runway engineering surveys under complex topographic conditions in hilly areas.Through comprehensive sur-vey methods,the engineering properties of fill soil,silty clay,and bedrock in the site area were sys-tematically evaluated.The research findings indicate that although compacted fill soil possesses certain shear strength,its uniformity is relatively poor,necessitating strict control of construction quality.Soft plastic silty clay exhibits high compressibility and low strength characteristics,making it unsuita-ble as a foundation bearing layer.The engineering properties of bedrock vary significantly,with mod-erately weathered sandstone demonstrating favorable mechanical performance,while mudstone rocks show poor water stability.The weak shear characteristics at the interface between fill soil and bedrock significantly impact the stability of high slopes,requiring special treatment measures.The research outcomes provide important design basis and engineering practical experience for airport construction under similar topographic conditions,offering guidance for ensuring the safe operation of airports in hilly regions and those involving high fill sections.

Abstract:In order to study the distribution of welding temperature field and stress field of hydraulic support connecting rod,the welding process of connecting rod was simulated by SYSWELD software.The results show that the analysis of the temperature field shows that there are differences in the thermal cycle curves of different paths.There are two temperature peaks(1 710℃ and 2 290℃)in the thermal cycle curve of the acquisition point at the side plate and the cover plate,and there are two temperature peaks(1 834℃ and 1 924℃)in the thermal cycle curve of the acquisition point at the transverse weld and the vertical weld of the vertical plate.The analysis of the stress field shows that the longitudinal residual stress is mainly distributed in strips,and the transverse residual stress is mainly distributed in columns,and the longitudinal stress accounts for a relatively high proportion in the total stress.At the same time,by analyzing the residual stress distribution curve ofS1path,it is found that the residual stress distribution curve is symmetrically distributed due to the influence of each heat source.The values gradually decrease from the maximum values of 468 MPa,382 MPa and 256 MPa to the minimum values of 78 MPa,34 MPa and 25 MPa,and then gradually increase,and decrease again after a certain distance.The research results provide a reference for the related research in the field of hydraulic support welding.

Abstract:The roughness of rock joints,as a critical parameter governing the mechanical behavior of rock mass interfaces,necessitates in-depth investigation into its correlation with shear strength for significant engineering implications.In this study,molds were initially fabricated using 3D printing technology to cast interface contact specimens with varying roughness levels(Joint Roughness Coeffi-cient JRC=3,8,13,18,21).Oblique shear tests at 45° inclination were conducted on these specimens through a WAW-2000 microcomputer-controlled electro-hydraulic servo universal testing machine,ac-quiring load-displacement curves for interfaces with distinct roughness characteristics.The influence patterns of roughness on shear behavior were systematically analyzed,while Digital Image Correlation technique was concurrently employed for dynamic monitoring of displacement and strain fields.The research findings demonstrate that joint roughness exerts a significant influence on the shear strength of interface contact specimens.The JRC value substantially affects the failure morphology,with shear strength exhibiting a positive correlation with increasing JRC values.Enhanced roughness induces a transition in shear failure mode from the sliding of filling materials to structural failure,revealing that surface morphology plays a decisive role in controlling the mechanical behavior of rock mass interfaces.This investigation provides quantitative evidence for understanding the roughness-dependent shear mecha-nisms in rock discontinuity systems.

Abstract:In order to speed up the construction progress of Xianglushan Tunnel in the Dianzhong Water Diversion Project,a new 27 shaft is added between the 4th and 5th slant holes to increase the construction working faces.The"straight hole+S hole"surface pre-grouting for shaft is used for the first time in hydraulic engineering.The stratum of the lower part of 27 shaft is andesitic basalt.Seg-mented downward grouting in the broken stratum of andesitic basalt become the key and difficult point of construction.According to the degree of rock fragmentation,a variety of technical measures for downward grouting and technical measures to prevent borehole accidents are studied.Because of the implementation of these measures,the safety of the KWS packer in the hole was realized;the grouting construction progress and grouting quality was effectively guaranteed.

Abstract:During the drilling,blasting and support construction of the frozen shaft,in order to prevent the layout of blast holes and the support of anchor rods from damaging the frozen holes,the BIM(Building Information Modeling)technology was used to digitally model,visually present and dataize the objects of the shaft and the surrounding environment that adopted the frozen shaft sinking method.After on-site construction verification,the output results have a good guiding effect on the excavation and masonry construction of the shaft,enhance the safety guarantee of the frozen effect of the shaft,indirectly improve the safety of the construction site,and have a good reference significance for the shaft freezing method construction under the same conditions.

Abstract:The loose and deformed areas of the surrounding rock in different parts of deep soft rock tun-nels show a significant non-uniform distribution.Quantitative selection of the key areas where the sur-rounding rock is prone to"failure"is necessary to promptly strengthen the support and ensure the sta-bility of these areas.This will help maintain the overall stability of the tunnel surrounding rock and has important engineering application prospects.By using the widely used multi-point displacement meters in engineering,the surface deformation of typical areas of the tunnel surrounding rock is moni-tored,and the characteristics of the primary creep of the surrounding rock are analyzed.The speed of secondary creep after the tunnel excavation causes the surface deformation is used as the evaluation in-dex to determine the degree of difficulty of"failure"for the representative parts of the tunnel,and to identify the key parts prone to"failure".This provides a basis for determining the key parts of the tunnel surrounding rock and promptly strengthening the support.

Abstract:Aiming at the law of gas occurrence and effective prevention and control in extra-thick coal seams,taking the 8119 working face of Tashan Coal Mine as the engineering background,the experi-mental determination of gas basic parameters,the field test of effective gas extraction radius and the numerical simulation method are comprehensively used,and the field verification is further carried out through the gas extraction effect.The gas adsorption constant a of the coal sample in the 8119 work-ing face is 19.997 m3/(t·r),and the b value is 0.359 MPa-1.The maximum coal seam gas content is 4.87 m3/t,and the maximum coal seam gas pressure is 0.22 MPa.The permeability coefficient of coal seam is 11.29 m2/(MPa2·d);the initial emission intensity q0 of the borehole is 4.92 m3/min,and the attenuation coefficient α of the borehole gas flow is 0.066 d-1.When the effective extraction radius of gas is 1.5 m and the extraction time is 138 d,the optimal gas extraction effect is achieved.This con-clusion is consistent with the field verification and evaluation results.

Abstract:At present,the ground horizontal grouting reinforcement technology is one of the effective methods and means for preventing and controlling floor water gushing.The ground exploration and treatment project of the floor karst water exploration and treatment in the 11 mining area of Liangbei No.2 Coal Mine of Henan Pingmei Coal Industry relies on the ground directional horizontal branch drilling grouting technology,conducting drilling exploration and grouting treatment on the ground.This method explores concealed structures and water-conducting channels while investigating and grouting the top of the Taiyuan Formation lower limestone or Cambrian limestone aquifers to achieve safe mining under pressure.The research results show that,through the analysis of the geological structures revealed by the surface branch holes and the analysis of the grouting volume,it was deter-mined that in the target layer area of the lower limestone of the Taiyuan Formation(L1+L2),the de-velopment of karst fractures is not high,and local fractures are developed in the Cambrian limestone layer,indicating a relatively complex geological condition.The study's design included one main hole and 31 branch holes,which together explored 20 faults.Grouting reinforcement was carried out at the identified leakage points,meeting the expected treatment requirements.This research provides valua-ble reference for the study of surface directional horizontal branch drilling grouting technology and re-gional grouting treatment.

Abstract:Most of the base cracks are caused by their own internal factors or the non-load stress gener-ated under the action of environmental temperature and humidity changes.Water diffusion forms a relative humidity gradient in cement-stabilized gravel,leading to uneven shrinkage of water-stabilized gravel.This paper considers the effect of water diffusion on rubber water-stabilized gravel,the early humidity field inside is simulated.The results show that the shrinkage of the beam model is smaller than the shrinkage of the suspended dense structure.The 15 d dry shrinkage of the cement stabilized gravel beam model is linearly reduced.The shrinkage was minimized when the rubber powder was 1.5％of the aggregate mass.When the rubber dosage is certain,the random polygon shrinkage resist-ance is the best,and the oval aggregate shrinkage resistance is the worst.Among the three particle si-zes,the rubber particles with 2 mm particle size have the best resistance to shrinkage,so it can be speculated that a reasonable rubber particle size range is the most beneficial for the shrinkage resist-ance of rubber water stabilized gravel.

Abstract:In view of the frequent occurrence of high-energy microseismic events in isolated coal bodies in 7303 working face of Zhaolou Coal Mine,the overall instability impact mechanism of isolated coal bodies in fully mechanized top-coal caving face with deep topsoil was studied by means of numerical simulation,theoretical analysis and industrial test,and the following conclusions were drawn:the e-volution law of stratum spatial structure in fully mechanized top-coal caving face with deep topsoil was discussed,the estimation model of fully mining abutment pressure in fully mechanized top-coal caving face with deep topsoil was established,and the instability criterion of overall impact of isolated coal bodies in fully mechanized top-coal caving face with deep topsoil was deduced.The overall impact mechanism of isolated coal body in fully mechanized top-coal caving face with deep overburden is re-vealed:the high level of supporting pressure of surrounding rock of the face comes from the primary soil arch structure in the state of quasi-full mining,and the stress concentration of surrounding rock is increased after the superposition of stratum self-weight and structural stress,and at the same time,the roadway cuts the surrounding rock of the face to form a high-stress isolated coal body.When the bearing stress in the elastic core area exceeds its failure threshold,the isolated coal body will have an overall unstable rock burst.

Abstract:The Pingdingshan Coal Mine is facing a prominent problem of tight coal mining and excava-tion succession.The TBM(Tunnel Boring Machine)excavator,with its efficient,safe and mechanized features,has become a powerful tool for rock tunnel excavation in coal mines.This paper studies the"Pingmei Shield No.1"EQC5530 full-section hard rock excavator,elaborates on the advan-tages of the full-section open-type shield machine in rapid tunneling in coal mine rock tunnels,and combines its application situation in the third row of gangue conveyor of Pingmei the 13th Mine,mainly analyzing and summarizing from aspects such as TBM equipment design and key components,TBM rapid support during excavation,TBM transportation system guarantee technology,and long-distance ventilation and cooling technology.The results show that the TBM equipment design meets the requirements for safe and rapid long-distance large-section complex geological tunneling;by opti-mizing the support design,the downtime caused by imbalance between excavation and support is re-duced;the existing transportation of materials and gangue conveying system is renovated to achieve the balance of excavation and transportation;the original ventilation system is renovated to achieve long-distance ventilation and cooling.The maximum single-shift advance is 10.8 m,the maximum sin-gle-day advance is 26 m,and the maximum monthly advance is 314.5 m,providing valuable experience and technical references for TBM tunneling in similar mines.