Cohesion Values Research Articles

Factors influencing static and cyclic behaviour of polymer-grouted sands

ABSTRACT In this study, thorough laboratory research was conducted in order to increase knowledge of the beneficial effect of water-soluble epoxy resin on the monotonic or cyclic triaxial strength of different sands. Seven sand fractions (with different particle sizes, uniformity coefficients and mineralogical compositions) were injected with solutions of epoxy resin and water, at ratios of 3.0, 2.0 and 1.5. To evaluate the influence of chemical treatment on the static strength behaviour of grouted sands, a series of monotonic triaxial tests on dry specimens and isotropically consolidated undrained (CIU) triaxial tests, were conducted on samples cured for 90 days. CIU cyclic triaxial compression tests were also performed, to assess improvements in the cyclic resistance of treated sands. The experiments showed that this resinous grouting resulted in an appreciable increase in cohesion values, particularly for fine sands and well-graded sands, ranging from 0.15 to 0.66 MPa. Despite the fact that friction angle values were reduced, the overall shear strength increased over a wide range of stresses. Moreover, all grouted sands exhibited a substantial improvement in cyclic properties, with failure occurring at significantly elevated stress levels and after enduring a larger number of loading cycles, compared to their untreated counterparts.

Exploiting the land use to predict shallow landslide susceptibility: A probabilistic implementation of LAPSUS-LS

Due to the significant role of land use on the occurrence of rainfall-induced shallow landslides, this factor is commonly employed as a landslide susceptibility predictor. However, the land use classification is oftentimes very broad, neglecting the proven mechanical and hydrogeological role of the land management on slope stability. Given the necessity of including spatially distributed and management-specific inputs, the process-based landscape evolution model LAPSUS-LS was chosen and adapted to achieve a probabilistic approach which takes into account land management as an input by adopting management-specific values of root cohesion. The model was applied to four test sites in the Oltrepò Pavese (Italy), where different vineyard management techniques play a significant role in triggering landslides. The results for the four test areas had, cumulatively, an Area Under the Roc curve greater than 0.73, with false negative cells being < 1 % of the total for all simulations. In the model’s application, land use practices characterised by higher root cohesion proved to benefit slope stability, whereas tilled vineyards, shrublands and abandoned vineyards were more prone to the formation of shallow landslides. In addition, we found that the inclusion of management-specific input parameters produced more accurate outputs and that in catchments characterised by average slope angles lower than 15°, varying the vineyard management, did not appear to affect the landslide susceptibility. Due to the model’s high dependency on the land use and its ability to include land management, it can take into account the spatial variability of input values such as the root cohesion. Additionally, it can be applied i) to manage current conditions, ii) to explore future land use change, iii) to study less invasive yet beneficial land use management change scenarios and iv) provide farmers of at-risk areas insight on how to improve slope stability.

Influence of shear strength parameters on loose fine sand treated with coir fiber and microbially induced calcite precipitation

In recent years, there has been an increasing use of Microbially Induced Calcite Precipitation (MICP) technology in ground improvement. Adding fiber to bio-cemented sand leads to significant improvements in its properties. This paper examines how coir fiber and microbially induced calcite precipitation (MICP) might be used to improve the engineering qualities of fine sand. The sand was mixed with Coir fiber at varying Fiber Contents (FC) of 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% by weight of sand. Additionally, varied Aspect Ratios (AR) of 45, 90, 136, 182, and 227 were considered. The mixture also included urease-producing bacteria (Sporosarcina Pasteurii), as well as solutions of urea and calcium chloride with 3M molarity. The untreated and treated sand samples were submitted to a Direct Shear Test (DST). The study found that the shear strength parameters, such as the angle of internal friction, increased by 1.1 times compared to standard fine sand. Additionally, the angle of internal friction (ϕ) of fiber-reinforced sand with MICP showed 1.4 times increase, while the cohesion values demonstrated a sixfold increase compared to MICP fine sand. It was determined that the optimal aspect ratio was 182, and the optimal fiber content was 0.3%. Moreover, the Scanning Electron Microscope (SEM) was utilized to examine the calcite formations present in the treated sand samples, and calcite precipitation was observed between the pores of the soils.

Slope Stability Analysis Throughout Road Around Bukit Barisan Selatan National Park (BBSNP) using Fellenius Method

Bukit Barisan Selatan National Park (BBSNP) is a nature conservation area in Indonesia. The slope stability of the interprovincial roads in BBSNP needs to be assessed for slope stability. This study assesses slope stability using the Fellenius method for the factor of safety calculation. The data utilized consists of geological and structure regional conditions, soil descriptions, soil physical and mechanical properties, water content, liquid limit, plastic limit, plasticity index, specific gravity, soil strength, slope dimensions, and slope weight. The sampling process is conducted un-disturb, followed by laboratory testing. The laboratory tests conducted include soil elasticity and plasticity, soil cohesion, and internal friction angle. The critical slopes at LT-L01 and LT-L23 are compromised due to the low cohesion values, making both slopes susceptible to landslides. The stable slope at LT-R04, LT-L15, LT-L19, and LT-R30 exhibit variability properties across the slopes. The lithology for slope LT-R04 consists of inorganic clay with high plasticity, slopes LT-L15 and LT-R30 have same lithology of silty clay with medium plasticity, while slope LT-L19 has lithology of silty clay with low plasticity. The safety factor values indicate stability due to moderate - high cohesion, contributing to slope stability. Material compaction is required to enhance cohesion values on the slopes. Additionally, need to mitigate water saturation conditions in the slope materials.

Psychological Resilience Following Disasters: A Study of Adolescents and Their Caregivers

Resilience, the process of successful adaptation to adverse circumstances, is traditionally studied as an individual characteristic. However, more recent multisystem perspectives underline the interrelatedness of systems, within and outside of the individual, in shaping coping and adaptation processes. This challenges the assumption that pathways to resilience are the same across the world, given the diversity in people’s contexts globally. In light of the preponderance of resilience research being conducted in higher-income countries, this study taps pathways to resilience in survivors of the 2018 earthquake-tsunami-liquefaction disaster in Central Sulawesi, Indonesia. Guided by a social representations approach and using a novel free association technique, forty caregiver-adolescent dyads (N = 80) who survived the disaster were interviewed regarding their subjective experiences of coping and adaptation. Thematic analysis of their narratives demonstrated that survivors focused on mutual support, religious beliefs and intrapersonal psychological resources of seeking strength and calmness as routes for fostering psychological recovery. The results foreground group-specific aspects of such resilience: differences between caregivers and adolescents highlight how social roles and life stage shape resilience-related beliefs and practices. Moreover, the form their resilience takes is underpinned by sociocultural values of reciprocity and social cohesion. Thus, this paper points to similarities in resilience processes across contexts, but also to differences shaped by societal roles, developmental stage and cultural values.

Evaluating the strength characteristics of mixtures of municipal solid waste incineration bottom ash and reddish laterite clay for sustainable construction

This study examines effects of mixing municipal solid waste incineration bottom ash (MSWI-BA) with reddish laterite clay (RLC), evaluating factors such as vertical stress, mixing ratio, curing period, and the addition of lime. A total of 153 direct shear tests were conducted to thoroughly assess the mixture's strength characteristics. Vertical stress levels of 85.5 kPa, 172.4 kPa, and 259.3 kPa were used to simulate varying stress conditions, while mixing ratios of 40 %, 80 %, 100 %, and 120 % were applied to explore potential applications of recycled MSWI-BA with clayey soils. A fast-curing approach was employed, with curing periods of 24, 48, and 72 h, to investigate the time-dependent strength development under controlled conditions. A three-way ANOVA analysis confirmed that mixing ratio, curing period, and vertical stress significantly impacted both peak and residual shear strength. The 100 % MSWI-BA mixture, with or without 1 % lime, exhibited optimal performance, providing the pronounced shear strengths and dilative behavior. The study found that MSWI-BA significantly improved shear strength ratios compared to the RLC, with improvement ratios ranging from 1.439 to 2.460 across stress levels. Additionally, upper and lower bound equations for peak and residual strength ratios were developed, providing predictive tools for mixture design. Cohesion values in the range of 8.3–128.9 kPa and friction angles from 40.6° to 44.1° were achieved, surpassing or matching those reported in similar research. The study employed Bolton's (1986) dilatancy model, finding α values between 0.61 and 0.71, comparable to those in studies of granular materials. These results highlight the effectiveness of adding MSWI-BA and lime in enhancing reddish laterite soil stabilization through both chemical and mechanical means, making it a sustainable and cost-effective approach for civil engineering projects by improving material strength, reusing local soils, recycling waste, and reducing carbon footprints.

Advantages of using DIC for capturing mechanical shear sliding behaviour of the FRCM strengthened masonry

This paper aims to analyse the advantages of using Digital Image Correlation (DIC) method to capture the effects of the FRCM on masonry wall shear failure. In the scientific literature, most of the experimental programs is focused on strengthening against flexural failure by means of bending tests and against shear, diagonal cracking, by means of diagonal compression tests. The shear failures are one of the main failure modes for the in-plane behaviour of masonry walls in case of horizontal loads. This study primarily focuses on experimentally determining the capacity of clay brick masonry under sliding shear loads for different normal stress levels with a standard test method. The assessment of shear capacity is based on a Mohr-Coulomb failure criterion depending on the external axial load, the internal friction angle and the cohesion values for unreinforced masonry. The experimental tests have been carried out on both unreinforced and strengthened specimens. The results of the tests demonstrate that FRCM, despite the reduced anchorage length in the tests, can significantly enhance the structural performance of masonry structures for sliding shear failure mode. In addition, DIC method is used to analyse, in greater detail, the cracks and the strain evolution in order to analyse the failure of specimens.

Impact of building topologies on hill slope stability in Aizawl city

In hilly regions like Aizawl city, wherein houses are mostly built on slopes, the layout of building plays a crucial role in slope stability. Building failures in Aizawl often results from a) non-engineered alterations of slopes b) faulty foundation construction without soil investigation or design. Many residents build and reside on slopes without considering the soil characteristics. To address this, a study was conducted to examine the impact of two common building types - step-back buildings and step-back setback buildings on slope stability in Aizawl. Fifty different sites with varying slope geometries were analysed using Limit Equilibrium Method (LEM), considering soil parameters like cohesion, internal friction angle, unit weight, and slope geometry. The study evaluated slope stability under conditions such as free slope, slope with building loads under static and seismic conditions. The study found that sites with lower slope angles generally demonstrated greater stability, but there were cases where steeper slopes showed better stability due to superior shear strength values. Sites with higher cohesion values exhibited better stability in free slope analysis, while those with higher internal friction angles showed better stability under building loads of both static and seismic condition. To validate the above findings, a sensitivity analysis along with a comparative analysis between step-back and step-back setback building types were conducted. The results indicated that step-back setback buildings offered better stability compared to step-back buildings alone. This suggests that implementing step-back setback buildings could significantly improve slope stability in cities like Aizawl.

Experimental study on the effect of freeze–thaw cycles to the cohesion and moisture content of geogrid reinforced silty clay

The freezing and thawing cycle is one of the primary causes of damage and instability to buildings in seasonal frost regions. During this process, the mechanical properties of soil are affected, leading to settlement, cracking, or deformation of infrastructure. Mitigating or reducing the occurrence of building frost damage in seasonal frost regions has become an important subject of study. Freeze–thaw (F–T) action will influence the distribution of moisture inside the reinforced soil and change the strength of thawing soil, which is closely related to the main influencing factors, such as initial moisture content, compaction degree, reinforced spacing, number of freeze–thaw cycles (FTC), freezing temperature, and effective vertical stress. Cohesion is an important index to determine the shear strength of clay, which is important to analyze the change in cohesion after F–T. Meanwhile, cohesion is closely related to soil moisture content. This study conducted orthogonal experiments on these primary influencing factors (6 factors at 5 levels) through FTC tests, triaxial tests, and moisture content tests to determine the undrained cohesion and moisture content of the clay after FTC, thereby establishing the influence of reinforcement on soil strength under freeze–thaw conditions. Based on the experimental results, SPSS software was used to fit the regression equations of undrained cohesion and moisture content expressed by the main influencing factors at different heights of the clay. Optimization options for the main influencing factors were obtained with Matlab software when the highest undrained cohesion values 6.8, 10.6, 8.9 kPa and lowest moisture content values 24.0%, 24.3%, 26.2% appeared in upper, middle and lower parts of the testing clay structure respectively, in conditions of − 15 °C freezing temperature and 5 times FTC. And determined the optimal combinations of moisture content, reinforcement spacing, compaction density, and vertical load at different heights. Decreasing reinforced spacing in silty clay was beneficial for liquid underwater seepage after F–T. The redistribution of internal moisture in the soil sample strengthened its undrained cohesion, thereby increasing the soil's shear strength. Comparing reinforcement conditions at different locations, it was found that when there were 3 layers of reinforcement with a spacing of 150 mm between them, this spacing was optimal. It played a significant role in improving the soil's shear strength and enhancing its bearing capacity. For reinforced clay itself, the order of the main factors influencing the undrained cohesion of soil after F–T, from high to low, was initial moisture content, reinforced spacing, and compaction degree.

Investigation of Particle Gradation Effect on Soil-Rock Mixture Using Direct Shear Test

Soil-rock mixture (SRM) is a special geomaterial that is composed of soil and a certain percentage of rock blocks with various sizes and strengths. It has high structural strength and renewable resources that are used as filler in subgrade, construction material and embankment dams. However, the mechanical properties of the soil-rock mixture are sophisticated owing to the complicated interaction between soil and rock particles. Previously, many experimental investigations were conducted to focus on shear behaviours and the influencing factors of SRM. Yet, limited w ork has been done to underline the effect of particle size distribution towards SRM shear strength parameters. Thus, this study conducted an SRM shear test with three different kinds of gradation and rock block percentages. Various soil densities, porosities and different framework structures have resulted from different rock particle concentrations. From the results, the well-graded SRM shows a non-linear trend of cohesion value while uniformly graded and gap-graded SRMs shows contradicting trend respectively. The result and analysis in this study are especially useful in analysing its influence on the shear strength parameters of SRM with different rock block percentages.

Study on the Mechanical Properties of Roots and Friction Characteristics of the Root–Soil Interface of Two Tree Species in the Coastal Region of Southeastern China

The tensile strength of roots and the friction characteristics of the root–soil interface of tree species are the indicators that play a crucial role in understanding the mechanism of soil reinforcement by roots. To calculate the effectiveness of the reinforcement of soil by tree roots based on essential influencing parameters, typical trees in the coastal region of southeastern China selected for this study were subjected to tests of the tensile mechanical properties of their roots, as well as studies on the friction characteristics of the root–soil interface and the microscopic interfaces. The results indicated that in the 1–7 diameter classes, the root tensile strength of both Pinus massoniana and Cunninghamia lanceolata was negatively correlated with the root diameter in accordance with the power function. The root tensile strength of these two trees, however, was positively correlated with the lignin content but negatively correlated with cellulose and hemicellulose contents. The shear strength at the root–soil interface and the vertical load exhibited a constitutive relationship, which followed the Mohr–Coulomb criterion. As the root diameter increased, both the cohesion and the friction coefficients at the root–soil interface gradually increased, but the growth rate stood at around 15%. The cohesion value of the root–soil interface of the two trees decreased linearly with the increase in soil moisture content within the range of 25 to 45%. At the microinterface, the root surface of C. lanceolata exhibited concave grooves and convex ridges that extended along the axial direction of roots, with their height differences increasing with the enlargement of the root diameter. The rough surface of P. massoniana roots had areas composed of polygonal meshes, with an increase observed in the mesh density with increasing root diameter.

Mechanical behavior of calcareous tuff and coal mine tailings mixture as an embankment material for road construction

The construction of embankments requires available and suitable material that sounds to the imposed load. The selection of materials that provide slope stability and maintain pavements is made through specific test control. This research aims to analyze the mechanical behavior of a mixture of 75% calcareous tuff and 25% coal mine tailings (CMTs) used on embankment foundations. the impact of particle size characteristics and the compaction on the mechanical behavior of the mixture are studied. The direct shear test was conducted on different material states, granular and uncompressed states, compaction at the Maximum Practical Optimum (MPO), and MPO compaction post a 30-day curing period at 40 degrees Celsius. the normal stress applied ranging from 50 to 500 KPa, with a constant shear rate displacement of 0.5 mm/min. The results show a substantial influence of compaction on both friction angle (φ) and cohesion (C) values. a remarkable increase in cohesion values after the curing period, attributed to the cementitious compound formation from the interaction between calcareous tuff and coal mine tailings. This investigation emphasizes coal mine tailings potential as a sustainable and cost-effective embankment material for road construction, especially in arid regions. The material exhibits significant shear strength, with a marked increase in cohesion values post-curing state. These results are conducted to consider coal mine tailings as an appealing alternative to traditional materials of road engineering.

Analisis Penggunaan Tanaman Vetiver terhadap Stabilitas Lereng pada Bendungan Way Sekampung

Problems that occur in the western part of As Way Sekampung have the potential for landslides to occur. Efforts used to handle slope strengthening by planting vetiver plants. The research method used to analyze slopes uses the limit equilibrium method on slip surface sections using the Morgenstren-Price method with the help of Geostudio 2023.1.0 software. SLOPE/W to get the safety factor under normal conditions and under seismic load conditions. By using a seismic load with a return period of 500 years (PE 10% in 50 years) with a Peak Ground Acceleration (PGA) value for the Way Sekampung Dam inundation area of 0,265 g. In vetiver plants, the root depth is simulated according to the top soil depth of 0,0 – 0,1 m. Soil planted with vetiver plants experienced an increase in the value of cohesion (c) by 74,42% and a decrease in the value of the angle of internal friction (φ˚) by 49,40%. The conclusion obtained was that slope stability in normal existing conditions was 4,525 and in normal vetiver plant strengthening conditions the safety factor increased to 4,529. Then, in the existing seismic conditions, the safety factor is 2,624 and in strengthening vetiver plants with seismic loads, the safety factor value increases to 2,626. It can be concluded that vetiver plants are able to strengthen slope conditions.

Perspectives of Maranao People at Zamboanga del Sur about Halal Food

This study provides insights into the broader context of religiosity and cultural and societal aspects of Halal consumption from the viewpoints of Maranaoans in Zamboanga del Sur, Philippines. It highlights the growing interest in Halal food markets around the world and its particular significance to the Maranaoan community, which is primarily Muslim living in a multicultural environment. It emphasises how strategic it is to comprehend how people thinks about Halal cuisine to promote inclusion and Filipino economic development within the Halal food industry. The study conducted in-depth interviews with Five Maranaoan respondents using a qualitative technique. The results were interpreted using thematic analysis, with an emphasis on the participants' knowledge, attitudes, and behaviours as well as the socio-cultural and religious elements impacting their views on Halal food. The findings highlight the value of cultural identity, community cohesion, and religious observance while revealing a deep regard for Halal culinary customs. However, they also point to difficulties, including the lack of awareness among non-Muslims in the area and the accessibility of Halal-certified goods and labelling. The participants conveyed their wish for Halal practices to be more widely acknowledged and respected in the community and the local food business. This study has numerous implications. Understanding the Maranaoan perspective on Halal food can help stakeholders and policymakers create inclusive policies and marketing strategies that address the ethical, cultural, and religious aspects of the Halal food sector. Furthermore, increasing the availability and understanding of Halal food can foster economic opportunities and social cohesiveness inside and outside the Maranaoan community. This study adds to the body of knowledge regarding cultural identity, religious eating customs, and the dynamics of Halal food consumption in multicultural environments. Keywords: Custom; Halal Food; Inclusiveness

Fusion of finite element and machine learning methods to predict rock shear strength parameters

Abstract The trial-and-error method for calibrating rock mechanics parameters has the disadvantages of complexity, being time-consuming, and difficulty in ensuring accuracy. Harnessing the repeatability and scalability intrinsic to numerical simulation calculations and amalgamating them with the data-driven attributes of machine learning methods, this study uses the finite element analysis software RS2 to establish 252 sets of sandstone sample data. The recursive feature elimination and cross-validation method is employed for feature selection. The shear strength parameters of sandstone are predicted using machine learning models optimized by the particle swarm optimization (PSO) algorithm, including the backpropagation neural network, Bayesian ridge regression, support vector regression (SVR), and light gradient boosting machine. The predicted value of cohesion is proposed as the input feature to predict the friction angle. The results indicate that the optimal input characteristics for predicting cohesion are elastic modulus, Poisson's ratio, peak stress, and peak strain, while the optimal input characteristics for predicting friction angle are peak stress and cohesion. The PSO-SVR model demonstrates the best performance. The maximum error between the predicted values of cohesion and friction angle and the calculated results of RSData program are 3.5% and 4.31%, respectively. The finite element calculation is in good agreement with the stress–strain curve obtained in the laboratory. The sensitivity analysis indicates that SVR's prediction performance for cohesion and friction angle tends to be stable when the sample size is &amp;gt;25. These results offer a valuable reference for accurately predicting rock mechanics parameters.

Tidal Seismicity in the Moon and Implications for the Rocky Interior of Europa

Seismology is a powerful tool for probing the deep interiors of planetary bodies. Just as deep moonquakes triggered by Earth’s tides occur on the Moon, as observed by the Apollo seismometers, icy moons of the giant planets may also have seismically active deep interiors, opening up future prospects for in situ seismic investigations at their surfaces. Of notable interest is Jupiter’s moon Europa, with its dynamic ice shell and potentially habitable subsurface ocean. In this work, we use different interior models of the Moon and model the tidal stress inside them to determine the most likely times and locations for the triggering of tidal moonquakes. Using the Mohr–Coulomb failure criterion, we derive cohesion and friction values for the lunar interior to match the observations of deep moonquakes by Apollo at a depth between 700 and 1200 km. By extending the same approach to different interior models of Europa, we show that Europa quakes triggered by the tides of Jupiter are 10 times more likely to occur than tidal moonquakes. The strength and depth of these tidal Europa quakes (euroquakes) strongly depend on the interior structure, with stronger events at the core–mantle boundary for liquid core models, while solid core models can be more prone to failure at the bottom of the ocean floor. Models without a metallic core favor failure in the upper third of the mantle with event strength similar to that in the solid core models.

Numerical Approach to Appreciate the Interaction of Two Neighbouring Shallow Foundation on a Cohesive and Partially Cohesive Soil

The program (cast3m) produced for us tables of values of stresses, displacements, images characterising stresses, displacements and deformations with their corresponding graphs. The results were presented as part of this study. It has been found that: two shallow closed foundations seriously affect the soil between them regardless of the soil type. Then, when the foundation is at same level in the different soil type and stress values are extracted in the zone of the cohesive soil (soft clay). A horizontal separation to width of foundation ratio was 0.7 and an influence equation was 0.333 if values of stresses are extracted from the partially cohesive soil (sandy clay). As per the vertical variation of the foundation in the different soil type. Independent of the soil type and the depth variation, a vertical separation to width of foundation ratio of 0.333 was observed. As the cohesion increases, the soil becomes denser which account for the high limit compressive stress compared to inferior values of cohesion. Finally, it is seen as a result of this research that the type of soil has a great rule to play as far as the interaction between two foundations is concern. An interaction led to failure when the foundation had a vertical gap between it that did not meet the above equation.

Enhancing clayey soil performance with lime and waste rubber tyre powder: Mechanical, microstructural, and statistical analysis

Nowadays, for soil stabilisation and cleaner production of geo-composites, the possibility of utilizing waste rubber is in vogue. The present paper deals with experimentally investigating the mechanical and micro-structural characteristics of weak Indian clayey soil partially substituted with lime (0–3.5%) and waste rubber tyre powder (0–15%). It was observed that, with increasing lime and rubber powder content, the plasticity index of the soil decreases. The shear strength and compaction testing results reveal that adding lime and rubber tyre powder (RTP) enhances the geotechnical performance of clayey soil up to an optimum dosage value. Also, the tri-axial shear testing was performed to obtain stress-strain curves for all considered soil mixes. For modified clayey soil containing 3% lime and 12.5% rubber powder, the cohesion values and bearing capacities improved phenomenally by 36.1% and 88.6% respectively, when compared to clayey soil. Further for this mix, SEM analysis reveals a compacted microstructure which improves dry-density and California's bearing ratio among all modified mixes. The novel co-relations upon regression analysis are found able to predict plasticity index, dry density, bearing capacity and shear strength with higher confidence levels. Overall, the cost-benefit analysis worked out to obtain the optimum cost of construction of footings and flexible pavement shows cost deductions up to 19% and 39% respectively while utilizing modified clay soil mixes containing 3% lime and 12.5% rubber powder in subgrade, ultimately making production stronger, cheaper and environment friendly.

Study on Shear Failure Process and Zonal Disintegration Mechanism of Roadway under High Ground Stress: A Numerical Simulation via a Strain-Softening Plastic Model and the Discrete Element Method

Fracture expansion in rock masses can be observed by monitoring the break of contacts between the bounding particles via the discrete element method. The latter’s realization in this study via the PFC2D program tracked the evolution process of the zonal disintegration in an exemplary roadway-surrounding rock affected by mining. Besides, the damage evolution pattern in a high-stress soft rock roadway was simulated by the FLAC2D program using a strain-softening plastic model, revealing the effects of rock mass strength, stress state, and anchor support on the zonal disintegration of the roadway. Numerical simulation results show that in a roadway with high-level stress, the obvious fractures spread from the roadway surface to the depth of the surrounding rock along a series of geometric planes and cut the surrounding rock into rock mass blocks. Under high crustal stress, conjugate shear fractures occur near the roadway surfaces and form a closed-loop fractured zone after intersecting the conjugate fracture faces. The closed fractured zone becomes a free face, from which conjugate shear fractures develop, forming new closed fractured zones in the deep surrounding rock. By repeatedly generating the closed fracture zones, a fracture network appears in the roadway-surrounding rock. The development of zonal disintegration of roadway-surrounding rock mainly depends on the rock mass strength and its stress state. Zonal disintegration only occurs when the crustal stress of the roadway-surrounding rock exceeds its strength. When the horizontal stress is low and the vertical stress exceeds the rock mass strength, zonal disintegration only occurs on two sides of the roadway. When the vertical stress is low and the horizontal stress exceeds the rock’s mass strength, it only appears on the roof and floor. When the values of cohesion, internal friction angle, and tensile strength are reduced in the same proportion, cohesion has the greatest impact on the expansion of the zonal disintegration zone, followed by the internal friction angle, while the tensile strength effect is the least. In anchor-supported roadways undergoing zonal disintegration processes, the intact zone blocks slide relatively along the fracture surface during the process of loosening and deformation of the surrounding rock, making the anchor rods susceptible to tensile, shear, and bending actions.

MINE SLOPE DESIGN SIMULATIONS USING SLIDE 6.0 SOFTWARE OF POST-MINING SLOPE STABILITY

Post-mining slopes are susceptible to landslides due to factors such as slope geometry, rock structure, physical and mechanical properties of rocks, and groundwater content. Monitoring of these slopes is essential to prevent broader environmental issues. This research aims to determine the stability of former mining slopes using soil samples from the Mataraman District, Banjar Regency. The technical analysis method focuses on the physical and mechanical properties of soil, supplemented with mine slope design simulations using Slide 6,0 software to ascertain the safety factors from various slope angles. Safety factor analysis considers the smallest cohesion and bulk density values to represent the material strength of the slope. Findings indicate that the post-mining slopes would remain stable and safe provided no additional destabilizing factors are introduced. The slopes maintain a safety factor greater than 2, implying stability even with a steepness up to 70°. Keywords: mining slope stability, safety factor