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4 pages, 162 KiB

Open AccessEditorial

Advancing Sustainability in Geotechnical Engineering

by Shuren Wang, Chen Cao and Hongwei Yang

Sustainability 2024, 16(11), 4757; https://doi.org/10.3390/su16114757 - 3 Jun 2024

Viewed by 1223

Abstract

Geotechnical engineering is a key element for all engineering construction that establishes contact with the earth, including foundation engineering, slope engineering, tunnel engineering, mining engineering, etc [...] Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

Research

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14 pages, 6486 KiB

Open AccessArticle

Laboratory Experimental Study on the Pressure Relief Effect of Boreholes in Sandstone under High-Stress Conditions

by Xiaowei Lu, Jingyu Jiang, Wen Wang, Xuewen Cao and Lei Hong

Sustainability 2023, 15(21), 15557; https://doi.org/10.3390/su152115557 - 2 Nov 2023

Viewed by 860

Abstract

To study the effects of deep rock drilling pressure relief under high stress conditions in enhanced geothermal systems, two kinds of drilling pressure relief experiments were conducted on sandstone—the staged drilling of pressure relief holes before peak stress and one-time drilling. Pressure relief [...] Read more.

To study the effects of deep rock drilling pressure relief under high stress conditions in enhanced geothermal systems, two kinds of drilling pressure relief experiments were conducted on sandstone—the staged drilling of pressure relief holes before peak stress and one-time drilling. Pressure relief experiments were carried out on sandstone with two borehole methods of the stage-by-stage drilling and one-time drilling of pressure relief boreholes ahead of the experiments. FLAC3D was used to analyze the plastic zone evolution during drilling and the relationship between stress and plastic zone volume. The results reveal the pre-peak stress change characteristics and pressure relief features of non-prefabricated boreholes under high stress. The experiments show that the staged drilling of pressurized samples involves stages of rapid and gradual decreases in stress, with total relief amplitudes increasing but single-borehole relief decreasing with more holes. Under the same conditions, staged drilling has better relief effects and results in greater energy dissipation, indicating that incremental pre-peak pressure relief is beneficial for reducing the surrounding rock’s impact tendency and improving stability. The research results can provide good guidance and reference for the long-term stability analysis of borehole-containing rock and rock burst hazard control. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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21 pages, 7432 KiB

Open AccessArticle

Analysis of Surface Settlement Induced by Shield Tunnelling: Grey Relational Analysis and Numerical Simulation Study on Critical Construction Parameters

by Minhe Luo, Ding Wang, Xuchun Wang and Zelin Lu

Sustainability 2023, 15(19), 14315; https://doi.org/10.3390/su151914315 - 28 Sep 2023

Cited by 3 | Viewed by 1080

Abstract

Excessive surface settlement poses significant challenges to shield tunnelling construction, resulting in damage to adjacent buildings, infrastructure, and underground pipelines. This study focused on investigating the surface settlement induced by shield tunnelling during the construction of Qingdao Metro Line 6 between Haigang Road [...] Read more.

Excessive surface settlement poses significant challenges to shield tunnelling construction, resulting in damage to adjacent buildings, infrastructure, and underground pipelines. This study focused on investigating the surface settlement induced by shield tunnelling during the construction of Qingdao Metro Line 6 between Haigang Road Station and Chaoyang Road Station. Firstly, the settlement data from the left line of the shield tunnel were evaluated by grey relational analysis. The relational coefficients were calculated to assess the correlation degrees of each influential parameter. Subsequently, the four critical influential parameters with the highest relational degrees were chosen to investigate their effects on surface settlement through numerical simulations under different scenarios. The results show that the four parameters with the highest relational degrees were thrust, grouting pressure, earth pressure, and strata elastic modulus. It should be noted that the strata elastic modulus significantly affects surface settlement, while the grouting pressure influences the settlement trough width in weak strata. Moreover, improper thrust magnitude can lead to an increase in surface settlement. Based on these findings, recommendations are proposed for the right-line tunnel construction and practical countermeasures for surface settlement during shield tunnelling construction are provided. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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21 pages, 7148 KiB

Open AccessArticle

Study on the Stress Distribution and Stability Control of Surrounding Rock of Reserved Roadway with Hard Roof

by Yuxi Hao, Mingliang Li, Wen Wang, Zhizeng Zhang and Zhun Li

Sustainability 2023, 15(19), 14111; https://doi.org/10.3390/su151914111 - 23 Sep 2023

Cited by 2 | Viewed by 962

Abstract

According to field observation and theoretical analysis, the failure of the 1523103 reserved roadway is mainly affected by the lateral support pressure, rock mass strength, and support mode. With the mining of the 152309 working face, the lateral pressure of coal pillars on [...] Read more.

According to field observation and theoretical analysis, the failure of the 1523103 reserved roadway is mainly affected by the lateral support pressure, rock mass strength, and support mode. With the mining of the 152309 working face, the lateral pressure of coal pillars on both sides of the reserved roadway increases, and since the lithology of the two sides and the floor of the roadway is weak, the reserved roadway experiences spalling and floor heave. Through numerical simulation, the distribution law of surrounding rock stress and the displacement of surrounding rock are obtained after the roof cutting and pressure relief of the reserved roadway with hard roof. According to the cause of surrounding rock failure of a reserved roadway, the combined control technology of roof cutting and pressure relief, grouting anchor cable support, and bolt support is put forward. After cutting the roof and releasing the pressure on the working face, the lateral support pressure of the two sides of the roadway is significantly reduced, the deformation of the two sides of the roadway is small, the maximum shrinkage rate of the section is reduced from 70% to 11%, and the deformation of the surrounding rock of the 1523103 reserved roadway is effectively controlled. The successful control of the surrounding rock in the 1523103 tunnel reduces the number of coal pillars to be installed, improves the coal extraction rate, and is conducive to the sustainable utilization of limited natural resources and the sustainable development of the coal industry. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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17 pages, 9240 KiB

Open AccessArticle

Experimental Study of the Mechanical and Acoustic Emission Characteristics of Sandstone by Using High-Temperature Water-Cooling Cycles

by Wen Wang, Lei Hong, Xuewen Cao, Xiaowei Lu, Fan Wang, Tong Zhang and Weibing Zhu

Sustainability 2023, 15(18), 13358; https://doi.org/10.3390/su151813358 - 6 Sep 2023

Cited by 2 | Viewed by 939

Abstract

In order to study the physical and mechanical properties of sandstone under high-temperature water-cooling cycling conditions, an RMT-150B electrohydraulic servo rock testing system and a DS-5 acoustic emission detection and analysis system were used to conduct uniaxial compression acoustic emission tests on sandstone [...] Read more.

In order to study the physical and mechanical properties of sandstone under high-temperature water-cooling cycling conditions, an RMT-150B electrohydraulic servo rock testing system and a DS-5 acoustic emission detection and analysis system were used to conduct uniaxial compression acoustic emission tests on sandstone after high-temperature water-cooling cycles. The deformation, strength, and acoustic emission characteristics of sandstone were analyzed under different temperatures and cycle times. The results show that the high-temperature water-cooling effect caused changes in the physical properties of sandstone. The volumetric expansion rate of the rock samples first decreased, then increased in temperature, and the strength first increased, then decreased, whereas the number of cycles had less of an impact on the physical properties. At 200 °C, with increased cycle number, the elastic modulus increased by 20.1%, and the compressive strength increased from 63.9 MPa to 71.46 MPa. At 300–600 °C, the elastic modulus and compressive strength of sandstone gradually decreased with increases in the temperature and cycle number, with reductions of 6.04%, 7.24%, 28.7%, 35.57%, 17.6%, 18.2%, 20.4%, and 60.5%, respectively. With increased temperature and cycle times, the acoustic emission ringing counts increased, ringing counts and cumulative energy appeared earlier, the rock samples entered elastic deformation earlier, the yield stage length increased, and the samples showed a tendency to transition from brittle to ductile damage. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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16 pages, 5049 KiB

Open AccessArticle

Damage Mode and Energy Consumption Characteristics of Paper-Sludge-Doped Magnesium Chloride Cement Composites

by Shuren Wang, Zhixiang Wang, Jian Gong and Qianqian Liu

Sustainability 2023, 15(17), 13051; https://doi.org/10.3390/su151713051 - 30 Aug 2023

Cited by 2 | Viewed by 913

Abstract

To reduce the pollution caused by paper sludge in the environment and overcome issues of poor water resistance and brittleness in Magnesium Oxychloride Cement (MOC), the MOC was modified by adding different dosages of paper sludge. The mechanical properties and damage modes of [...] Read more.

To reduce the pollution caused by paper sludge in the environment and overcome issues of poor water resistance and brittleness in Magnesium Oxychloride Cement (MOC), the MOC was modified by adding different dosages of paper sludge. The mechanical properties and damage modes of composite MOC materials containing paper sludge were studied by uniaxial compression tests. Under cyclic loading conditions, the damage progression of MOC composites was characterised using the tensile-shear conversion factor (Tsc) and by monitoring the energy parameters (elastic strain energy, plastic strain energy and dissipation energy). The results show that the average peak stress drop of MOC composites gradually increases with the increase in paper sludge dosage. Under uniaxial compression conditions, the Tsc of the MOC composites decreases from 0.99 to 0.44, and the damage mode is transitioned from brittle tensile damage to tensile-shear damage, X-shaped conjugate surface shear damage and finally to pure shear damage with an increase in doping. During cyclic loading conditions, the brittleness of MOC composites gradually decreases with an increase in paper sludge doping, which verifies the effect of paper sludge on the mechanical properties of MOC materials and the change in damage modes from the perspective of energy dissipation. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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15 pages, 5071 KiB

Open AccessArticle

Experimental Study on the Solidification of Uranium Tailings and Uranium Removal Based on MICP

by Lin Hu, Zhijun Zhang, Lingling Wu, Qing Yu, Huaimiao Zheng, Yakun Tian and Guicheng He

Sustainability 2023, 15(16), 12387; https://doi.org/10.3390/su151612387 - 15 Aug 2023

Cited by 4 | Viewed by 1184

Abstract

The governance of uranium tailings aims to improve stability and reduce radionuclide uranium release. In order to achieve this goal, the uranium removal solution test and uranium tailings grouting test were successively carried out using microbially induced calcium carbonate precipitation (MICP) technology. The [...] Read more.

The governance of uranium tailings aims to improve stability and reduce radionuclide uranium release. In order to achieve this goal, the uranium removal solution test and uranium tailings grouting test were successively carried out using microbially induced calcium carbonate precipitation (MICP) technology. The effect of MICP on the reinforcement of uranium tailings and the synchronous control of radionuclide uranium in the tailings were discussed. The solution test results show that Sporosarcina pasteurii could grow and reproduce rapidly in an acidic medium with an initial pH of 5. The uranium concentration decreased with the increase in MICP reaction time, and the removal efficiency reached 60.9% at 24 h. In the solidification test of tailings, the strength of tailings improved significantly after 12 days of reinforcement, with an increase in the cohesion of tailings by 2.937 times and an increased internal friction angle of 8.393°. The peak stress value of solidified tailings at the surrounding pressure of 50 kPa increased by 1.87 times, and the uranium concentration in the discharge fluid decreased by 76.91% compared to the blank group. This study provides valuable insights and references for safely disposing of uranium tailings. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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16 pages, 7183 KiB

Open AccessArticle

Geological Strength Index Relationships with the Q-System and Q-Slope

by Samad Narimani, Seyed Morteza Davarpanah, Neil Bar, Ákos Török and Balázs Vásárhelyi

Sustainability 2023, 15(14), 11233; https://doi.org/10.3390/su151411233 - 19 Jul 2023

Cited by 2 | Viewed by 3194

Abstract

The Q-system and Q-slope are empirical methods developed for classifying and assessing rock masses for tunneling, underground mining, and rock slope engineering. Both methods have been used extensively to guide appropriate ground support design for underground excavations and stable angles for rock slopes. [...] Read more.

The Q-system and Q-slope are empirical methods developed for classifying and assessing rock masses for tunneling, underground mining, and rock slope engineering. Both methods have been used extensively to guide appropriate ground support design for underground excavations and stable angles for rock slopes. Using datasets obtained from igneous, sedimentary, and metamorphic rock slopes from various regions worldwide, this research investigates different relationships between the geological strength index (GSI) and the Q-system and Q-slope. It also presents relationships between chart-derived GSI with GSI estimations from RMR89 and Q’ during drill core logging or traverse mapping. Statistical analysis was used to assess the reliability of the suggested correlations to determine the validity of the produced equations. The research demonstrated that the proposed equations provide appropriate values for the root mean squared error value (RMSE), the mean absolute percentage error (MAPE), the mean absolute error (MAE), and the coefficient of determination (R-squared). These relationships provide appropriate regression coefficients, and it was identified that correlations were stronger when considering metamorphic rocks rather than other rocks. Moreover, considering all rock types together, achieved correlations are remarkable. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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17 pages, 5329 KiB

Open AccessArticle

Spatial Effect Analysis of a Long Strip Pit Partition Wall and Its Influence on Adjacent Pile Foundations

by Nan Zhou and Jianhui Yang

Sustainability 2023, 15(13), 10409; https://doi.org/10.3390/su151310409 - 1 Jul 2023

Viewed by 1101

Abstract

The spatial effect at the end of the foundation pit partition wall is significant, and the displacement of the retaining wall and soil caused by its demolition leads to an additional displacement and bending moment of the adjacent pile foundations, which in turn [...] Read more.

The spatial effect at the end of the foundation pit partition wall is significant, and the displacement of the retaining wall and soil caused by its demolition leads to an additional displacement and bending moment of the adjacent pile foundations, which in turn deteriorates the work behavior of the pile foundation. Taking the project of an open tunnel under a viaduct located in Hangzhou as an example, site monitoring was performed to determine the effect of the demolition of the partition wall on the displacement of the surrounding retaining wall and the soil in the adjacent area and the monitoring data were compared to the finite element analysis results to check the rationality of the finite element model. This model was used to study the influence of the distance from the pile foundation to the partition wall as well as the stiffness of the retaining wall on the displacement and bending moment of the pile foundation during excavation. These results indicate that because of the support effect of the foundation pit partition wall on the retaining wall, the spatial effect at the end of the partition wall is large, and the displacement and bending moments of the pile foundation in the vicinity of the partition wall are lower than those in the far distance. Demolition of the partition wall will increase the displacement and bending moment of adjacent pile foundations, and this effect decreases with increasing distance. The range of influence of the spatial effect at the end of the partition wall is approximately 1.1 times the depth of the foundation pit. When the pile foundation is in the immediate vicinity of the partition wall, the response of the front-row and rear-row piles to the demolition of the partition wall is significantly different. The front row piles are more affected, while the rear row piles are less affected. As the distance increases, the difference in response gradually decreases and tends to be consistent. As the stiffness of the retaining wall increases, the effect of the demolition of the partition wall on the pile foundation decreases. It is recommended that the stiffness of the supporting system near the partition wall be reduced appropriately, and the partition wall should be set at the foundation pit section near the pile foundation, but the response of the foundation pit and the adjacent pile foundation should be paid close attention to when the partition wall is demolished. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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13 pages, 3616 KiB

Open AccessArticle

Influence of Gas Pressure on the Failure Mechanism of Coal-like Burst-Prone Briquette and the Subsequent Geological Dynamic Disasters

by Ying Chen, Zhiwen Wang, Qianjia Hui, Zhaoju Zhang, Zikai Zhang, Bingjie Huo, Yang Chen and Jinliang Liu

Sustainability 2023, 15(10), 7856; https://doi.org/10.3390/su15107856 - 11 May 2023

Cited by 1 | Viewed by 1359

Abstract

Rock bursts and coal and gas outbursts are geodynamic disasters in underground coal mines. Laboratory testing of raw coal samples is the dominant research method for disaster prediction. However, the reliability of the experimental data is low due to the inconsistency of the [...] Read more.

Rock bursts and coal and gas outbursts are geodynamic disasters in underground coal mines. Laboratory testing of raw coal samples is the dominant research method for disaster prediction. However, the reliability of the experimental data is low due to the inconsistency of the mechanical properties of raw coal materials. The utilization of structural coal resources and the development of new coal-like materials are of significance for geodynamic disaster prediction and prevention. This paper studies the failure characteristics and dynamic disaster propensities of coal-like burst-prone briquettes under different gas pressures. A self-made multi-function rock–gas coupling experimental device was developed and burst-prone briquettes were synthesized, which greatly improved the efficiency and precision of the experimental data. The results showed that the burst proneness of the briquette was thoroughly reduced at a critical gas pressure of 0.4 MPa. When the gas pressure was close to 0.8 MPa, both the bearing capacity and the stored burst energy reduced significantly and the dynamic failure duration extended considerably, indicating the typical plastic-flow failure characteristics of coal and gas outbursts. The acoustic emission monitoring results showed that with the increase in gas pressure, the post-peak ringing and the AE energy ratio of coal samples increased, suggesting that the macroscopic damage pattern changed from bursting-ejecting of large pieces to stripping–shedding of small fragments adhered to mylonitic coal. In addition, the transformation and coexistence of coal failure modes were discussed from the perspectives of coal geology and gas migration. This study provides a new method for the scientific research of compound dynamic disaster prevention in burst coal mines with high gas contents. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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20 pages, 4421 KiB

Open AccessArticle

Proposed Method for the Design of Geosynthetic-Reinforced Pile-Supported (GRPS) Embankments

by Rashad Alsirawan, Edina Koch and Ammar Alnmr

Sustainability 2023, 15(7), 6196; https://doi.org/10.3390/su15076196 - 4 Apr 2023

Cited by 8 | Viewed by 1946

Abstract

Soft soils with unfavorable properties can be improved using various ground-improvement methods. Among these methods, geosynthetic-reinforced pile-supported (GRPS) embankments are considered a reliable option for challenging ground conditions and time-bound projects. Nevertheless, the intricate load transfer mechanism of the GRPS embankment presents challenges [...] Read more.

Soft soils with unfavorable properties can be improved using various ground-improvement methods. Among these methods, geosynthetic-reinforced pile-supported (GRPS) embankments are considered a reliable option for challenging ground conditions and time-bound projects. Nevertheless, the intricate load transfer mechanism of the GRPS embankment presents challenges due to the multiple interactions among its components. To overcome the limitations of current design methods that do not fully account for all interactions, a simplified design method has been developed for GRPS embankments. This method uses numerical analysis to predict pile load efficiency and geosynthetic tension. In this study, a validated model of the GRPS embankment, which incorporates certain simplifications for design purposes, was adopted. Based on this simplified model, a database of load efficiency and geosynthetic tension was collected to derive the design equations. The design method employed six parameters, namely, pile cap width, pile spacing, embankment height, oedometric modulus of the subsoil, geosynthetic stiffness, and embankment fill unit weight. The design process utilized Plaxis 3D and Curve Expert software. The results showed reasonable agreement between the findings of the proposed design method and the field measurements of eight case studies. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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17 pages, 9914 KiB

Open AccessArticle

Dynamic Characteristics of Rock Holes with Gravel Sediment Drilled by Bit Anchor Cable Drilling

by Kuidong Gao, Jihai Liu, Hong Chen, Xu Li and Shuan Huang

Sustainability 2023, 15(7), 5956; https://doi.org/10.3390/su15075956 - 29 Mar 2023

Cited by 2 | Viewed by 1340

Abstract

Gravel and sediment frequently build up in holes during the anchor cable installation process, which makes it harder to install the anchor cable and causes reinforcement to fail, which can lead to accidents. In this paper, a bit anchor setup approach is proposed [...] Read more.

Gravel and sediment frequently build up in holes during the anchor cable installation process, which makes it harder to install the anchor cable and causes reinforcement to fail, which can lead to accidents. In this paper, a bit anchor setup approach is proposed to set up a drill bit at the front of the anchor cable to aid the anchor cable drilling. The feasibility of this approach is established with the aid of DEM-MBD joint simulation and proves the correctness of the simulation model. The major elements affecting drilling effectivity have been studied by the use of ‘check + simulation’. The effects exhibit that the axial velocity and working aperture are negatively correlated with the drilling resistance of the anchor cable; the feed price is positively related to the anchor cable drilling resistance; with the increase in anchor cable pitch, the drilling resistance of the anchor cable changes into a hump shape. When the bit is 0.2 m from the backside of the hole, the particle pace vector at the decrease stop of the bit gives a conical distribution. This paper is of fantastic magnitude in relation to the environment-friendly setup of anchor cables and protection against disasters. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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22 pages, 17824 KiB

Open AccessArticle

Using Electric Field to Improve the Effect of Microbial-Induced Carbonate Precipitation

by Jinxiang Deng, Mengjie Li, Yakun Tian, Zhijun Zhang, Lingling Wu and Lin Hu

Sustainability 2023, 15(7), 5901; https://doi.org/10.3390/su15075901 - 28 Mar 2023

Cited by 5 | Viewed by 1833

Abstract

The precipitation of calcium carbonate induced by Sporosarcina pasteurii (S. pasteurii) has garnered considerable attention as a novel rock and soil reinforcement technique. The content and structure of calcium carbonate produced through this reaction play a crucial role in determining the [...] Read more.

The precipitation of calcium carbonate induced by Sporosarcina pasteurii (S. pasteurii) has garnered considerable attention as a novel rock and soil reinforcement technique. The content and structure of calcium carbonate produced through this reaction play a crucial role in determining the rocks’ and soil’s reinforcement effects in the later stages. Different potential gradients were introduced during the bacterial culture process to enhance the performance of the cementation and mineralization reactions of the bacterial solution to investigate the effects of electrification on the physical and chemical characteristics, such as the growth and reproduction of S. pasteurii. The results demonstrate that the concentration, activity, and number of viable bacteria of S. pasteurii were substantially enhanced under an electric field, particularly the weak electric field generated by 0.5 V/cm. The increased number of bacteria provides more nucleation sites for calcium carbonate deposition. Moreover, as the urease activity increased, the calcium carbonate content generated under an electric potential gradient of 0.5 V/cm surpassed that of other potential gradient groups. The growth rate increased by 9.78% compared to the calcium carbonate induced without electrification. Significantly, the suitable electric field enhances the crystal morphology of calcium carbonate and augments its quantity, thereby offering a novel approach for utilizing MICP in enhancing soil strength, controlling water pollution, and mitigating seepage. These findings elevate the applicability of microbial mineralization in engineering practices. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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15 pages, 11907 KiB

Open AccessArticle

Stability Analysis of Tunnel Surrounding Rock When TBM Passes through Fracture Zones with Different Deterioration Levels and Dip Angles

by Mingtao Ji, Xuchun Wang, Minhe Luo, Ding Wang, Hongwei Teng and Mingqing Du

Sustainability 2023, 15(6), 5243; https://doi.org/10.3390/su15065243 - 15 Mar 2023

Cited by 3 | Viewed by 2742

Abstract

In fracture zones, tunneling with a double-shield Tunnel Boring Machine (TBM) presents significant challenges, including deformation overrun of the surrounding rock, TBM jamming, and excavation face collapse. To assure the tunnel construction safety and efficiency, it is necessary and crucial to conduct a [...] Read more.

In fracture zones, tunneling with a double-shield Tunnel Boring Machine (TBM) presents significant challenges, including deformation overrun of the surrounding rock, TBM jamming, and excavation face collapse. To assure the tunnel construction safety and efficiency, it is necessary and crucial to conduct a stability analysis of the tunnel surrounding rock when a TBM passes through the fracture zones. The tunnels from Jiadingshan Road Station to Anshan Road Station in Qingdao Metro Line 8 are constructed by double-shield TBMs. It inevitably passes through fracture zones with different deterioration levels and dip angles. In this study, based on this construction section, numerical models of fracture zones with different deterioration levels and dip angles were developed to analyze the displacements of tunnel vaults, inverts, and haunches. In addition, the maximum shear stresses of the surrounding rock were analyzed. Finally, the displacement and shear stress variation patterns of the surrounding rock with different deterioration levels and dip angles were obtained. The findings reveal the stability behavior of tunnels under various fracture zones. They can serve as a valuable reference and theoretical foundation for future tunnel construction projects utilizing double-shield TBMs in areas with fracture zones. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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18 pages, 7150 KiB

Open AccessArticle

Nonlinear Finite Element Analysis of a Composite Joint with a Blind Bolt and T-stub

by Jincheng Hua, Xinwu Wang, Huanhuan Liu and Haisu Sun

Sustainability 2023, 15(6), 4790; https://doi.org/10.3390/su15064790 - 8 Mar 2023

Viewed by 1391

Abstract

A detailed nonlinear finite element model was established based on completed experiments to investigate the behavior of a blind-bolted T-stub composite joint that connects a composite beam to a concrete-filled square tube column. This was accomplished by comparing the experimental results and the [...] Read more.

A detailed nonlinear finite element model was established based on completed experiments to investigate the behavior of a blind-bolted T-stub composite joint that connects a composite beam to a concrete-filled square tube column. This was accomplished by comparing the experimental results and the finite element simulation results using the hysteresis curve, failure mode, plastic deformation and strain development of the T-stub to ensure the reliability and accuracy of the finite element model. A parametric study was carried out on the base model to expand the library of test data. It was observed from the comparison that the proposed nonlinear FE model predicted the behavior of the composite joint. The wall thickness of the column and reinforcement ratio had a significant influence on the ultimate bending moment of the composite joint and the performance of the composite joint was mainly controlled by the reinforcement ratio when the concrete slab was under a positive bending moment. The flange of the T-stub, the web of the T-stub and the axial compression ratio had little effect on the performance of the composite joint. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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14 pages, 5273 KiB

Open AccessArticle

One-Dimensional Computational Model of Gyttja Clay for Settlement Prediction

by Grzegorz Kacprzak, Artur Zbiciak, Kazimierz Józefiak, Paweł Nowak and Mateusz Frydrych

Sustainability 2023, 15(3), 1759; https://doi.org/10.3390/su15031759 - 17 Jan 2023

Cited by 3 | Viewed by 1428

Abstract

One of the most important subjects of geomechanics research is finding mathematical relationships which could correctly describe behavior of the soil under loading. Safety of every engineering structure depends strongly on accuracy and correctness of this description. As laboratory tests show, macroscopic properties [...] Read more.

One of the most important subjects of geomechanics research is finding mathematical relationships which could correctly describe behavior of the soil under loading. Safety of every engineering structure depends strongly on accuracy and correctness of this description. As laboratory tests show, macroscopic properties of soil are complicated. Therefore, working out appropriate load-settlement relationships is considered to be a very difficult geomechanics tasks to solve. A majority of constitutive models proposed to date concern mineral soils and there is very little research related to modelling organic soil behavior under loading. In case of organic soils, due to their very complicated and composite structure, constitutive models are often formulated empirically based on laboratory tests of particular soils. The authors of this paper propose a 1-D rheological structure which accounts for complex behavior of soil related to the settlement process. The model simulates immediate reversible elastic settlement and plastic soil deformation as well as primary and secondary (creep effect) consolidation. Material parameters of the model were determined by a curve fitting procedure applied for a natural scale settlement test of plate foundation. The test was carried out in soil conditions connected with Eemian geological structure of Warsaw, i.e., Eemian glacial tunnel valley in Warsaw called Żoliborz Glacial Tunnel Valley filled with organic soils being up to 20 metres thick. This area has lately become an object of interest of investors as a site for building construction. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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19 pages, 19161 KiB

Open AccessArticle

Study on the Influence of Water Content on Mechanical Properties and Acoustic Emission Characteristics of Sandstone: Case Study from China Based on a Sandstone from the Nanyang Area

by Xin Huang, Tong Wang, Yanbin Luo and Jiaqi Guo

Sustainability 2023, 15(1), 552; https://doi.org/10.3390/su15010552 - 28 Dec 2022

Cited by 4 | Viewed by 2071

Abstract

In order to study the influence of water content on the mechanical properties of sandstone and evolution of crack propagation, laboratory compression tests and Engineering Discrete Element Method (EDEM) numerical simulation of sandstone under different conditions were carried out by the RMT-150B rock [...] Read more.

In order to study the influence of water content on the mechanical properties of sandstone and evolution of crack propagation, laboratory compression tests and Engineering Discrete Element Method (EDEM) numerical simulation of sandstone under different conditions were carried out by the RMT-150B rock mechanics test system. The sandstone samples were from Nanyang, Henan Province, containing a total of 12 rock samples. Under the confining pressure of 0, 5, 10, and 20 MPa, the rock samples with 0%, 1.81%, and 3.24% water content were tested. The findings demonstrated that as the sample’s water content grew, the peak strain increased but the peak strength, elastic modulus, maximum energy rate of individual acoustic emission events, and cumulative acoustic emission energy rate all reduced. While the ratio of tensile cracks to shear cracks inside the rock samples rose with increasing water content, the failure mode of sandstone changes from shear failure to tensile failure with the increase of water content, but the sandstone specimens in the three conditions exhibited shear macroscopic fracture surfaces. Research results will provide reference for the safe construction of underground projects in water rich areas. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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Review

Jump to: Editorial, Research

36 pages, 13296 KiB

Open AccessReview

A State-of-the-Art Review and Numerical Study of Reinforced Expansive Soil with Granular Anchor Piles and Helical Piles

by Ammar Alnmr, Richard Paul Ray and Rashad Alsirawan

Sustainability 2023, 15(3), 2802; https://doi.org/10.3390/su15032802 - 3 Feb 2023

Cited by 14 | Viewed by 4294

Abstract

Expansive soils exist in many countries worldwide, and their characteristics make them exceedingly difficult to engineer. Due to its significant swelling and shrinkage characteristics, expansive soil defies many of the stabilization solutions available to engineers. Differential heave or settlement occurs when expansive soil [...] Read more.

Expansive soils exist in many countries worldwide, and their characteristics make them exceedingly difficult to engineer. Due to its significant swelling and shrinkage characteristics, expansive soil defies many of the stabilization solutions available to engineers. Differential heave or settlement occurs when expansive soil swells or shrinks, causing severe damage to foundations, buildings, roadways, and retaining structures. In such soils, it is necessary to construct a foundation that avoids the adverse effects of settlement. As a result, building the structure’s foundations on expansive soil necessitates special consideration. Helical piles provide resistance to uplift in light structures. However, they may not fully stabilize foundations in expansive soils. A granular anchor pile is another anchor technique that may provide the necessary resistance to uplift in expansive soils using simpler methods. This review and numerical study investigate the fundamental foundation treatments for expansive soils and the behavior of granular anchors and helical piles. Results indicate that granular anchor piles performed better than helical piles for uplift and settlement performance. For heave performance, the granular anchor and helical piles perform nearly identically. Both achieve heave reductions greater than 90% when L/H > 1.5 and D = 0.6 m. Full article

(This article belongs to the Special Issue Advancing Sustainability in Geotechnical Engineering)

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