Engineering Geological Conditions Research Articles

Experimental Study on Stability Analysis of Shallow-Buried Metro Station Hard Rock Excavation under Blasting Vibration Effect

Abstract By considering a certain metro station of Qingdao Metro Line 4 as the research object, a three-dimensional geotechnical testing model has been developed to analyze the stress and deformation characteristics of the surrounding rocks under blasting vibration effect. The simulation of the surrounding rock blasting process is achieved through an electric spark source. We conducted simulation tests on the excavation stability of shallow-buried hard rock metro stations with and without considering blasting damage effects, respectively. The stress, displacement, and primary support stress changing laws of the surrounding rock under different overburden thicknesses using the arch cover method and the primary support arch cover method have been revealed. Finally, we analyzed the applicability of the primary support arch cover method in terms of vault settlement, clearance convergence, and floor heave. Results show that the surrounding rock of the arch has roughly gone through three deformation stages, namely a slow deformation stage, rapid deformation stage, and stable deformation stage. Whether it is blasting excavation or non-blasting excavation, the settlement of the arch is within a safe and controllable range. Because of the refinement of the excavation process by the primary support arch cover method, the stress release is relatively stable throughout the entire excavation process, but the significant impact of blasting vibration on the surrounding rock cannot be ignored. The excavating of the left and right guide holes is the key process for the displacement and stress variation. The deformation and stress generated by the arch cover method have a small difference compared to the deformation and stress generated by the primary support arch cover method, indicating that the latter excavation method can be used under current engineering geological conditions. No large-area collapse and instability occurred in the experimental process, which provides a theoretical basis for similar projects.

Engineering-geological conditions and interactions of technogenic processes with the environment

Engineering-geological conditions and interactions of technogenic processes with the environment

Recommendation of excavation method and support system based on engineering geology at Riam Kiwa Dam diversion tunnel, South Kalimantan, Indonesia

River flow diversion is one of the most critical factors that must be considered for the success of dam construction. Soil and rock can support and load; therefore, understanding their strength and properties before tunnel construction is essential. Tunnel excavation and support depend totally on rock mass quality. Surface geological mapping, drill core analysis, and laboratory testing characterized the engineering geology conditions. Rock Mass Rating (RMR) and Japan Society of Civil Engineers (JSCE) methods were compared to determine rock mass quality and recommend excavation and support systems. Results showed that slightly weathered andesite lava and tuff lapilli lithologies dominate the tunnel alignment. Based on RMR, the rock masses quality along the tunnel alignment consists of poor and fair, and based on JSCE, the tunnel alignment consists of D I and C II rock categories with L and M massive rock types. Top heading and bench are recommended for tunnel excavation based on RMR, and the double bench and full-face method with an auxiliary bench cut are recommended for tunnel excavation based on JSCE. Although the characteristics of other support systems vary marginally, support systems based on RMR and JSCE recommend rock bolts and shotcrete as the primary tunnel support systems.

Analysis of Excavation Method on Inlet Tunnel of Controller Construction of Rukoh Dam Pidie District – Aceh Province

The tunnel of controller construction is located in Panton Bunot Village, Tiro Sub District, Pidie District, Aceh Province. The tunnel construction aims to flow the water from Kr. Tiro River to Rukoh inundation for water supply to Rukoh Dam in Keumala Sub District, Pidie District. The research aimed to comprehend engineering geological condition in the study area and determine excavation method at the inlet and proper tunnel support system. The determination of proper excavation method becomes crucial and it is required in maintaining affectivity and efficiency during tunnel construction process. Than excavation method determination is carried out calculation by using empirical method based on output parameter of laboratory test to the rock samples from core drilling in the tunnel track. The outputs are rock conditions as rock mass quality (RQD), discontinuity area density of the rock and rock stress strength. The condition of tunnel track was dominated by silt stone having very poor quality. UCS value was 3 Mpa – 10 Mpa. Joins spacing was less that 60 mm. Empirical analysis of excavation method explained that tunnel opening of Rukoh Controller Construction was highly weathered (HW) and required ripping as excavation type.

Geoecological and economic consequences of creation, drainage and possible variants of restoration the Kakhovsky reservoir

In the article, in the aspect of engineering and geological safety of structures and communications, the long-term hydrogeological consequences of the support and drainage effects at coastal areas of destroyed Kakhovsky hydro node reservoir as a leading eco-forming component of a giant natural and man-made geosystem are considered. In particular, it included Zaporizhia NPP, the largest in Europe, and the largest irrigation systems in Ukraine. The consequences of the hydrodynamic disaster due to explosion of Kakhovskaya HPP, the dynamics and current state of drainage of the bed of its reservoir are briefly described, according to the data of GIS analysis of space images. And also – the state of hydrogeological and engineering-geological conditions in the reservoir support zone at the time of disaster and in retrospect. A calculated assessment of changes in hydrogeological conditions for the next 10-15 years has been carried out. Long-term natural and man-made threats that arose as a result of such changes in hydrogeological (geofiltration and geodynamic) conditions are named. The set of socio-economic threats that arose due to the negative consequences of Kakhovsky reservoir existence and draining is described. It is emphasized that the restoration of hydrotechnical and water management parameters of the reservoir in the previous values (according to the conservative version) will lead to secondary geospatial water saturation of subsiding loess-loamy silty-clay floatingable rocks that have already undergone deformations due to a decrease in geotechnical stability during the initial flooding and subsequent drainage. This will start a new stage in the formation of dangerous violations of stress-deformed state of coastal slopes, of Zaporizhzhya NPP responsible structures foundation and in nearby cities and towns. A socially and ecologically favorable option for the rehabilitation of affected region is possible only on the modern European ideological and technological basis of taking into account the maximum permissible changes in the hydrological network, i.e. by means of: creating a cascade of low support channel reservoirs with locks and small hydroelectric power stations, reconstruction of riverside ponds and water supply systems, transfer of domestic water supply to underground sources, irrigated lands – for drip irrigation, ecological reclamation and afforestation of drained lands.

Study on the mechanism and response law of fracture movement on the super-high position hard-thick strata

In this paper, a thick plate structural mechanical model was established for the hard-thick rock strata in the Ordos region, which was characterized by the occurrence of high-energy strong earthquakes caused by the fracture of hard-thick rock strata. Subsequently, based on Vlasov's theory, the evolution process of hard-thick rock strata was analyzed. And the paper validated the analysis results using high-energy mine earthquake and surface subsidence data. The following conclusions were drawn: (1) The hard-thick strata in the cretaceous system will not be broken during the advancing and mining process of the test panel of the Shilawusu coal mine. (2) When the test panel is mined to a distance of two panel widths, no fracture occurred in the lower part of the hard-thick strata, because no separated space was formed. (3) When the test panel was advanced to about 856 m, the hard-thick strata have fractured in a vertical direction. (4) No high-energy mine earthquake event has occurred during mining at test panel, and the amount of surface subsidence is approximately 200 mm. (5) In the mining at test panel, two high-energy mining earthquakes occurred at 837 m, 1153 m away from the initial position of the panel, respectively, and the maximum amount of surface subsidence increased to 1397 mm, which accords with the results of the first and periodic breaks calculated by theory. The research results of this paper are of guiding significance for the study of the breaking law of hard-thick strata under similar engineering geological conditions and disaster pre-control.

Analysis of the influence of anchor piles on test results

The paper considers the main problems of design and calculation of deep foundations of high-rise buildings in the form of piles-barrettes. The results and methodology of field tests of barrette piles for the foundation of a 56-storey residential building in Moscow are presented. The characteristics of engineering-geological conditions of the future construction site and design solutions for pilot tests are presented. Given a large cross-section of the barrette, which involves a significant amount of pile-type soil mass with the formation of a complex stress-strain state, to obtain reliable results and verification of the calculated model is recommended to perform numerical tests in full compliance with the field experiment, taking into account the anchored piles. The paper describes the method and the results of the numerical calculation of the load-carrying capacity of a barrette taking into consideration the modeling of an anchoring system in the Midas GTS NX program complex by the finite-element method and shows the basic possibility of using the program complex and the described method for practical purposes with an admissible accuracy. The paper contains diagrams of vertical displacements of a barrette head as a function of the applied load in full-scale tests and a general evaluation of the carrying capacity of a barrette pile obtained by numerical solutions. It is found that by taking into account the anchoring system (beams and piles) in the numerical simulation, the calculation results obtained are the most accurate to the field tests in describing the behavior of the pile under load in comparison with the calculation of a single barrette pile. In spite of the fact that the barrette bottom is embedded into the rocky soils, the barrette piles are referred to the hanging piles according to the interaction conditions with the soil due to the significant load transfer along the lateral surface.

Influence of complex engineering geological and geotechnical conditions on the selection of combined measures for road landslide remediation

Influence of complex engineering geological and geotechnical conditions on the selection of combined measures for road landslide remediation

Engineering geological conditions for the construction of a photovoltaic power plant on coal tailings

Photovoltaic power plants have recently become increasingly common to reduce carbon emissions into the atmosphere. Non-fertile lands occupied by industrial waste are very suitable for their construction. The present study concerns the design and construction of a photovoltaic park on the territory of a reclaimed coal tailings dump “Suhoto Dere” near the TPP “Bobov Dol”. The study includes collection, processing and analysis of archival materials, site mapping, drilling of exploration boreholes, dynamic penetration tests, geophysical electrical resistivity survey, laboratory testing of soil samples to determine physical and mechanical properties; chemical analysis of soil samples to assess soil aggressiveness to concrete and steel. Based on the obtained data, an assessment of the suitability of the site is made and recommendations are given to prevent the occurrence of adverse phenomena and processes.

Emergency stabilization of a landslide in Pirin National Park

The investigated landslide occurred in December 2021 on a steep river-valley slope in the southwestern part of the Pirin National Park. It has a typical circular shape with approximate dimensions: width of 20 m, length of 15 m and depth up to 4 m. The sliding involves mainly the soil-rock mass of the road embankment. The landslide affects a forest road and threatens the hydraulic canal “Syrchaliytsa” of the “Sandanska Bistritsa” cascade. The study is based on an on-site inspection and geotechnical mapping, its analysis and interpretation, aided by available archival and published data, and the authors’ personal experience of similar sites in the area and other parts of the country. The main objectives are to establish the engineering-geological conditions of the terrain, assess the main factors defining the landslide stability and develop a conceptual solution for its strengthening.

Analysis of the impact of the combined use of rebar bolts and FRP bolts in the roadway enclosure

In order to investigate the support effect of the combination of FRP bolts and rebar bolts in the roadway, taking a coal mine as the background of the project, research and analysis of the engineering geological conditions of the mine and the layout of the mining roadway, stress analysis of the roadway peripheral rock, and put forward the combination of rebar and FRP bolts in the roadway peripheral rock support program. Based on different scenarios, FLAC3D was applied to simulate and analyze the distribution of axial force, maximum principal stress of the surrounding rock, yield damage of the surrounding rock, and displacement of the surrounding rock under three conditions: no support, full rebar bolt support, and combined rebar and FRP bolt support. The results show that (1) In the pre-action period between the bolt and the surrounding rock of the roadway, the FRP bolt carries the force first; in the late action period, the rebar bolt and the FRP bolt carry the force together. (2) From the analysis of the stress concentration degree of the maximum principal stress of the roadway surrounding rock, the horizontal displacement of the roadway surrounding rock and the distribution characteristics of the plastic zone of the roadway surrounding rock, it can be concluded that the support strength of FRP bolts is slightly lower than that of rebar bolts. (3) Under the state of combined support of FRP and rebar bolts, the range of plastic zone of surrounding rock in the roadway is analyzed in comparison with the effect of full rebar bolt support, and the range of reduction of plastic zone of surrounding rock is not obvious, and the effect of full rebar bolt support and combined support of FRP and rebar bolts on controlling the damage of surrounding rock is similar. (4) The side part of the roadway perimeter rock mining adopts FRP bolts instead of rebar bolts, and if the FRP bolts are not damaged, the combination of FRP and rebar bolts can be used for support, which can maintain the stability of the roadway perimeter rock.

Cейсмообусловленные опасные геологические явления и их распространение в восточном и юго-восточном Казахстане как отражение современных геодинамических процессов

The main factors determining engineering-geological conditions, patterns of development and spread of hazardous geological phenomena (HGE) in the territory of Eastern and South-Eastern Kazakhstan have been identified. The variety of geological, hydrogeological, engineering-geological, seismic conditions of the territory under consideration determines the development of various genetic types of dangerous geological phenomena, such as earthquakes, seismic dislocations, seismic landslides, landslides, screes, avalanches, mountain lakes, mudflows, etc. At present, especially It is important to carry out monitoring studies of HH in order to study the assessment of the scale of manifestations and reduce the damage from them.

A systematic review of clay shale research development for slope construction

The issue of stability controlling cutting slopes is particularly important in clay-shale slopes, a typical expanding sedimentary layer with poor engineering geological conditions and mechanical characteristics. Therefore, research on the causes of failure and remedies for clay-shale cutting slopes is required to serve as an overview for handling and preserving clay-shale slopes in identical conditions. However, the trusted information about the need for further related clay shale research and clay shale in slope stability has yet to be specifically presented. This review study summarizes the published research for clay shale beginning in 1980, presents a bibliometric analysis to examine the published research based on year and country, and provides various study trends in cluster diagram using the VOSviewer program. The analysis also summarized some key goals, effective methodology, and significant findings from the most recent studies to extract information from them that would benefit future research. In conclusion, the results show the need for developing research to fill the knowledge gap regarding clay shale, landslide, and clay mineralogy. In addition, the clay shale slope analysis has revealed the need for additional research into dynamic force and its deformation.

Analysis of the movement pattern of overburden and the form of spatial development of separation after mining in a fully mechanized caving face

For the fully mechanized caving face, it is easy to cause significant surface subsidence and other related problems after large-scale mining of coal seams, we should take some measures to solve them. In this study, in order to further explore the movement pattern of overburden and the form of spatial development of separation after mining in a fully mechanized caving face, we combined the engineering practice of Tangshan mining area, took the T2294 and T2291 working faces as the engineering background and used the three methods of similar simulation, numerical simulation and field measurement to comprehensively study. The results show that in the first stage of working face mining, the separation can generally reach 0.31 times the mining thickness of the coal seam, and the maximum can reach 0.58 times the mining thickness; in the second stage, the width of the separation seam is narrow, and the separation is small. It generally takes 20–30 days for the separation to reach its maximum from initiation, which is equivalent to the working face advancing 70–100 m, and the corresponding horizon height is 200 m. The research results provide theoretical guidance and a basis of engineering practice for the safe mining of multiple working faces under the Jingshan railway. This study even provides a basic theoretical reference for the safe mining of a thick coal seam working face under similar engineering geological conditions.

Multi-Scale Engineering Geological Zonation for Linear Projects in Mountainous Regions: A Case Study of National Highway 318 Chengdu-Shigatse Section

In response to the challenges of long crossing distances and difficult site selection for linear engineering projects in mountainous areas, this article proposes a multi-scale engineering geological zoning (EGZ) method. This method is based on the linear engineering construction stage and transitions from regional EGZ to EGZ of key sections (areas with poor or worst engineering geological conditions). This method not only ensures the effect of EGZ but also reduces the workload. When carrying out the EGZ of key sections, the assessment ideas of geological disaster hazards were taken into consideration. An improved method for calculating the time probability and magnitude probability of disaster occurrence is proposed. Taking the National Highway 318 Chengdu-Shigatse section as an example, EGZ was carried out. Its results revealed that the Nyingchi section was the key section with poor and worst engineering geological conditions. EGZ of the key section showed that the areas with poor and worst engineering geological conditions were mainly distributed in the curved sections on the northern side of the linear project. The proposed method in this article provides guidance for EGZ for linear engineering projects in mountainous areas.

Research on the Distribution of Overlying Rock Fractures Caused by Mining in Ultra-Thick Coal Seams and Its Impact on the Near-Surface Aquifer

Near-surface water is the foundation for maintaining the ecological environment, and coal remains an important energy source in today’s world as we face a shortage of green energy. Achieving near-surface-water protection while safely mining coal is an important way to ensure social and ecological health and sustainability. The key lies in whether the fracture height of the mining overlying strata affects the aquifer. This article compiles the coupling finite element and discrete element method (CFE-DEM) and established mechanical constitutive models such as the interaction between rock blocks on both sides of the penetrated fracture, rock mass fracture process, and the plastic deformation law of rocks based on the results of mining-induced overlying rock failure. On this basis, a numerical calculation model is established based on the engineering geological conditions of the Beixinyao Coal Mine. The numerical simulation results indicate that the theory and the CFE-DEM method can numerically simulate the distribution and evolution of mining-induced overlying rock fractures. The water-conducting fractures in the overlying strata of extra-thick coal seams extend to the front of the working face in a trapezoidal shape, and the angle formed between them and the advancing direction ranges from 62° to 75°. Combined with the in situ measurement results, the height of the water-conducting fracture zone of the extra-thick coal seam is between 209 m and 230 m; the fractures were not found to have affected the aquifer at a vertical distance of 252 m from the coal seam. This means that the impact of ultra-thick coal seam mining on the aquifer is very limited. The research is of great significance for ensuring coal mining and surface ecological sustainability in ultra-thick coal seam areas.

Numerical Simulation Study on Frost Heave during the Freezing Phase of Shallow-Buried and Undercut Tunnel Using the Freeze-Sealing Pipe Roof Method

This article begins with the engineering geological conditions and freezing design scheme of the Gongbei Tunnel’s underground excavation section, then applies the mathematical model theory of the horizontal freezing-tunnel-formation freezing temperature field and frost heave displacement field, and builds a coupled two-dimensional finite element calculation model. The development law of the frozen soil curtain and the variation law of frost heave displacement during the freezing phase were studied by comparing on-site observation data. According to the findings of this study, the construction of the artificial frozen curtain is mostly based on two types of freezing tubes that freeze the soil between jacked pipes and seal the water. At 90 days, the thickness of the frozen soil curtain ranges from 2.32 m to 2.58 m, guaranteeing that its strength fulfills water-sealing safety criteria. The distribution and variation of frost heave displacement are highly related to engineering geological circumstances, the freezing scheme, the frozen soil curtain development process, and the pipe curtain structure. The maximum vertical frost heave displacement value at any time is located at the centerline, which is 155.67 mm at 90 d. The numerical simulation findings are acceptable and can potentially be utilized for predicting frost heave in subsequent projects. More research is required to effectively represent complicated working conditions and to develop more exact large-scale numerical models for tunnel excavation, support structure building, and other situations.

Identification of Landslides Controlling and Triggering Factors using the Analytical Hierarchy Process (AHP) in Dermasuci Village, Pangkah District, Tegal Regency, Central Java Province - Indonesia

The National Disaster Management Agency (BNPB) stated that in 2022 around 634 landslides occurred in Indonesia. One of the regions in Indonesia that experienced landslide disasters is Dermasuci Village, Pangkah District, Tegal Regency, Central Java Province. The first landslide disaster occurred on February 5, 2022, and the second landslide occurred on February 10, 2022. The landslide disasters caused damage to 61 residents’ houses and four road sections. The objective of this study is to identify the controlling and triggering factors that mainly contributed to the landslide event. These two factors are determined based on the order of their static and dynamic properties using the analytical hierarchy process (AHP) method. Controlling and triggering factors of the landslide in the study area are determined based on geological and engineering geological conditions which were obtained from surface mapping results. The controlling factors obtained are the rock bedding inclination, geological structure in the form of faults, slope inclination, engineering properties of soil and rock, land use, and groundwater table. The triggering factors that are known and commonly occur are rainfall in the form of antecedents and intensity, and earthquakes that can induce landslides.

Modeling of long-term train loads impacts on subgrade soils: a review

Subgrade is an important construction element of the railroad track. In the process of long-term operation, the subgrade is loaded by trains and exposed to natural climatic factors, such as wind and seismic loads, moisture caused by atmospheric precipitations and groundwater, exposure to positive and negative temperatures. At the same time, the subgrade must provide reliability and stable properties of the railway track because its renovations are the most expensive ones among those for the railway track in general. Due to this fact, national regulatory documents for the construction of the subgrade impose strict requirements on its deformity for the entire duration of modern railways operation. One of the ways to solve this problem on the stage of construction designing is computer predictive modelling of structural behavior that considers the changes of its elements and properties of construction materials under the long-term train impact taking into consideration the varying natural climatic factors. In this review, we analyze accumulated scientific and technical experience in formulating optimal approaches to the determination of initial data for computer simulation of repeated impact of the train loads for predicting railway track subgrade deformation considering engineering-geological conditions and natural climatic factors. We describe the stages of creating the subgrade computer modelling taking into account the analysis of trains load impact, the properties of model’s structural layers, and the change of soil properties under long-term loads.

Surface runoff as a complicating factor of engineering geological conditions. design models by the example of Moscow

Climate change leads to changes in the volume and distribution of precipitation between seasons. Since water influences the course of most exogenous processes, the task of studying the formation of the connection between surface runoff and the spread of hazardous geological processes becomes relevant. A map of engineering and geological zoning, which is used in Moscow not only for design, but also in the current activities of services responsible for ensuring the safety of the operation of municipal services and environmental protection, was adopted as the initial information. The task is carried out on the Unified Digital Platform of Moscow in ArcGIS. The surface runoff model created on the basis of radar topographic survey is supplemented by methods for determining accumulation and depression zones, which makes it possible to identify areas of excessive soil moisture. Analysis of the intersection of zones of influence of surface runoff with taxa of engineering geological zoning makes it possible to quantify the distribution of connected objects, types of hazardous geological processes in zones of excessive moisture and adjust the assessment of the complexity of engineering geological conditions. As an example, the main regularities of the possible impact of surface runoff on increasing the risk of hazardous geological processes on the territory of cemeteries, cultural heritage sites and specially protected natural areas of Moscow are highlighted. It is proposed to use the methods of formation and analysis of the connection and the designed zones of influence of surface runoff in design, and monitoring systems, and in the current activities of city services.