Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.25.1.041
Assel Jumassultan, Nazerke Sagidullina, Jong R. Kim, T. Ku, Sung-Woo Moon
In cold regions, the integrity of the infrastructures built on weak soils can be extensively damaged by weathering actions due to the cyclic freezing and thawing. This damage can be mitigated by exploiting soil stabilization techniques. Generally, ordinary Portland cement (OPC) is the most commonly used binding material for investigating the chemo-hydro-mechanical behavior. However, due to the environmental issue of OPC producing a significant amount of carbon dioxide emission, calcium sulfoaluminate (CSA) cement can be used as one of the eco-sustainable alternatives. Although recently several studies have examined the strength development of CSA treated sand, no research has been concerned about CSA cement-stabilized sand affected by cyclic freeze and thaw. This study aims to conduct a comprehensive laboratory work to assess the effect of the cyclic freeze-thaw action on strength and durability of CSA cement-treated sand. For this purpose, unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests were performed on the stabilized soil specimens cured for 7 and 14 days which are subjected to 0, 1, 3, 5, and 7 freeze-thaw cycles. The test results show that the strength and durability index of the samples decrease with the increase of the freeze-thaw cycles. The loss of the strength and durability considerably decreases for all soil samples subjected to the freeze-thaw cycles. Overall, the use of CSA as a stabilizer for sandy soils would be an eco-friendly option to achieve sufficient strength and durability against the freeze-thaw action in cold regions.
{"title":"Performance of cement-stabilized sand subjected to freeze-thaw cycles","authors":"Assel Jumassultan, Nazerke Sagidullina, Jong R. Kim, T. Ku, Sung-Woo Moon","doi":"10.12989/GAE.2021.25.1.041","DOIUrl":"https://doi.org/10.12989/GAE.2021.25.1.041","url":null,"abstract":"In cold regions, the integrity of the infrastructures built on weak soils can be extensively damaged by weathering actions due to the cyclic freezing and thawing. This damage can be mitigated by exploiting soil stabilization techniques. Generally, ordinary Portland cement (OPC) is the most commonly used binding material for investigating the chemo-hydro-mechanical behavior. However, due to the environmental issue of OPC producing a significant amount of carbon dioxide emission, calcium sulfoaluminate (CSA) cement can be used as one of the eco-sustainable alternatives. Although recently several studies have examined the strength development of CSA treated sand, no research has been concerned about CSA cement-stabilized sand affected by cyclic freeze and thaw. This study aims to conduct a comprehensive laboratory work to assess the effect of the cyclic freeze-thaw action on strength and durability of CSA cement-treated sand. For this purpose, unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests were performed on the stabilized soil specimens cured for 7 and 14 days which are subjected to 0, 1, 3, 5, and 7 freeze-thaw cycles. The test results show that the strength and durability index of the samples decrease with the increase of the freeze-thaw cycles. The loss of the strength and durability considerably decreases for all soil samples subjected to the freeze-thaw cycles. Overall, the use of CSA as a stabilizer for sandy soils would be an eco-friendly option to achieve sufficient strength and durability against the freeze-thaw action in cold regions.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66475687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.24.6.559
K. Watcharasawe, P. Jongpradist, P. Kitiyodom, Tatsunori Matsumoto
This research presents the monitoring results and their interpretation on load sharing of the pile foundation during the construction of a high-rise (124 m in height) building in Bangkok, in soft clayey ground. Axial forces in several piles, pore water pressure and earth pressures beneath the raft in a tributary area were monitored through the construction period of the building. The raft of the pile foundation in soft clayey ground can share the load up to 10-20% even though the foundation was designed using the conventional approach in which the raft resistance is ignored. The benefit from the return of ground water table as the uplift pressure is recognized. A series of parametric study by 3D-FEA were carried out. The potential of utilizing the piled raft system for the high-rise building with underground basement in soft clayey ground was preliminarily confirmed.
{"title":"Measurements and analysis of load sharing between piles and raft in a pile foundation in clay","authors":"K. Watcharasawe, P. Jongpradist, P. Kitiyodom, Tatsunori Matsumoto","doi":"10.12989/GAE.2021.24.6.559","DOIUrl":"https://doi.org/10.12989/GAE.2021.24.6.559","url":null,"abstract":"This research presents the monitoring results and their interpretation on load sharing of the pile foundation during the construction of a high-rise (124 m in height) building in Bangkok, in soft clayey ground. Axial forces in several piles, pore water pressure and earth pressures beneath the raft in a tributary area were monitored through the construction period of the building. The raft of the pile foundation in soft clayey ground can share the load up to 10-20% even though the foundation was designed using the conventional approach in which the raft resistance is ignored. The benefit from the return of ground water table as the uplift pressure is recognized. A series of parametric study by 3D-FEA were carried out. The potential of utilizing the piled raft system for the high-rise building with underground basement in soft clayey ground was preliminarily confirmed.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66475719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.25.2.123
Wei Han, Yujing Jiang, Xuepeng Zhang, D. Koga, Yuan Gao
In this paper, the carbon fiber reinforced plastic (CFRP) grids embedded in polymer cement mortar (PCM) shotcrete (CFRP-PCM method) was conducted to repair the degraded tunnel linings with a cavity. Subsequently, the reinforcing effect of the CFRP-PCM method under different degrees of lining deterioration was quantitatively evaluated. Finally, the limit state design method of the M-N interaction curve was conducted to determine whether the structure reinforced by the CFRP-PCM method is in a safe state. The main results indicated that when the cavity is at the shoulder, the lining damage rate is more serious. In addition, the remarkably reinforcing effect on the degraded tunnel linings could be achieved by applying a higher grade of CFRP grids, whereas the optimization effect is no longer obvious when the grade of CFRP grids is too high (CR8); Furthermore, it is found that the M-N numerical values of the ten reinforcing designs of the CFRP-PCM method are distributed outside the corresponding M-N theoretical interaction curves, and these designs should be avoided in the corresponding reinforcing engineering.
{"title":"Quantitative assessment on the reinforcing behavior of the CFRP-PCM method on tunnel linings","authors":"Wei Han, Yujing Jiang, Xuepeng Zhang, D. Koga, Yuan Gao","doi":"10.12989/GAE.2021.25.2.123","DOIUrl":"https://doi.org/10.12989/GAE.2021.25.2.123","url":null,"abstract":"In this paper, the carbon fiber reinforced plastic (CFRP) grids embedded in polymer cement mortar (PCM) shotcrete (CFRP-PCM method) was conducted to repair the degraded tunnel linings with a cavity. Subsequently, the reinforcing effect of the CFRP-PCM method under different degrees of lining deterioration was quantitatively evaluated. Finally, the limit state design method of the M-N interaction curve was conducted to determine whether the structure reinforced by the CFRP-PCM method is in a safe state. The main results indicated that when the cavity is at the shoulder, the lining damage rate is more serious. In addition, the remarkably reinforcing effect on the degraded tunnel linings could be achieved by applying a higher grade of CFRP grids, whereas the optimization effect is no longer obvious when the grade of CFRP grids is too high (CR8); Furthermore, it is found that the M-N numerical values of the ten reinforcing designs of the CFRP-PCM method are distributed outside the corresponding M-N theoretical interaction curves, and these designs should be avoided in the corresponding reinforcing engineering.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66476068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.25.3.233
D. Kong, Y. Xiong, Zhanbo Cheng, Nan Wang, Guiyi Wu, Yong Liu
Rib spalling is a major issue affecting the safety of steeply inclined coal seam. And the failure coal face and support system can be affected with each other to generate a vicious cycle along with inducing large-scale collapse of surrounding rock in steeply inclined coal seam. In order to analyze failure mechanism and propose the corresponding prominent control measures of steeply inclined coal working face, mechanical model based on coal face-support-roof system and mechanical model of coal face failure was established to reveal the disaster mechanism of rib spalling and the sensitive analysis of related factors was performed. Furthermore, taking 3402 working face of Chen-man-zhuang coal mine as engineering background, numerical model by using FLAC3D was built to illustrate the propagation of displacement and stress fields in steeply inclined coal seam and verify the theory analysis as mentioned in this study. The results show that the coal face slide body in steeply inclined working face can be observed as the failure height of upper layer smaller than that of lower layer exhibiting with an irregular quadrilateral pyramid shape. Moreover, the cracks were originated from the upper layer of sliding body and gradually developed to the lower layer causing the final rib spalling. The influence factors on the stability of coal face can be ranked as overlying strata pressure (P) > mechanical parameters of coal body (e.g., cohesion (c), internal fraction angle (𝛟)) > support strength (F) > the support force of protecting piece (F
{"title":"Stability analysis of coal face based on coal face-support-roof system in steeply inclined coal seam","authors":"D. Kong, Y. Xiong, Zhanbo Cheng, Nan Wang, Guiyi Wu, Yong Liu","doi":"10.12989/GAE.2021.25.3.233","DOIUrl":"https://doi.org/10.12989/GAE.2021.25.3.233","url":null,"abstract":"Rib spalling is a major issue affecting the safety of steeply inclined coal seam. And the failure coal face and support system can be affected with each other to generate a vicious cycle along with inducing large-scale collapse of surrounding rock in steeply inclined coal seam. In order to analyze failure mechanism and propose the corresponding prominent control measures of steeply inclined coal working face, mechanical model based on coal face-support-roof system and mechanical model of coal face failure was established to reveal the disaster mechanism of rib spalling and the sensitive analysis of related factors was performed. Furthermore, taking 3402 working face of Chen-man-zhuang coal mine as engineering background, numerical model by using FLAC3D was built to illustrate the propagation of displacement and stress fields in steeply inclined coal seam and verify the theory analysis as mentioned in this study. The results show that the coal face slide body in steeply inclined working face can be observed as the failure height of upper layer smaller than that of lower layer exhibiting with an irregular quadrilateral pyramid shape. Moreover, the cracks were originated from the upper layer of sliding body and gradually developed to the lower layer causing the final rib spalling. The influence factors on the stability of coal face can be ranked as overlying strata pressure (P) > mechanical parameters of coal body (e.g., cohesion (c), internal fraction angle (𝛟)) > support strength (F) > the support force of protecting piece (F","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66476765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.25.6.473
Baran Toprak, S. Bas, I. Kalkan
The behavior of soil directly affects not only its stability condition but also structural response of structural systems. High-plasticity clay soil (CH) is vulnerable to volumetric swelling leading to different settlements in structural systems. Hence, it becomes indispensable to propose practical solutions to reducing this effect. In the present study, structural response of R/C frame buildings, resting on high plasticity clayey soils strengthened through the coal fly ash column technique, to earthquake motion is investigated. For this aim, the swelling behavior of high plasticity clay soil (CH) is identified with in-situ experimental tests on the regions with high swelling potential in the city of Kirikkale, Turkey. In order to reduce the swelling potential of the investigated regions, the coal fly ash column technique was implemented to the reference soil specimen with high swelling percentage of 15.6%. Experimental results obtained from the strengthened soil specimens were compared to those from the reference specimen. This comparison revealed that the coal fly ash column approach has a considerable effect on improving the swelling behavior of the high plasticity clay soil. The decrease in the volumetric swelling value is also thought to directly improve the response of a building structure settled on high plasticity clay soil. The improvement in the seismic response of existing R/C structures located in the regions with high swelling potential was identified by adopting the increased allowable bearing pressure value of the improved soil in the analyses. Based on the comparative study, structural earthquake response of R/C frame systems was investigated on the basis of the engineering parameters, including the base-shear force, base overturning moment, base axial force and settlement of foundation. The percent changes in these values showed that the base axial force and settlement of foundation were improved with the help of this strengthening application.
{"title":"Effects of fly ash column treatment of HP clayey soils on seismic behavior of R/C structures","authors":"Baran Toprak, S. Bas, I. Kalkan","doi":"10.12989/GAE.2021.25.6.473","DOIUrl":"https://doi.org/10.12989/GAE.2021.25.6.473","url":null,"abstract":"The behavior of soil directly affects not only its stability condition but also structural response of structural systems. High-plasticity clay soil (CH) is vulnerable to volumetric swelling leading to different settlements in structural systems. Hence, it becomes indispensable to propose practical solutions to reducing this effect. In the present study, structural response of R/C frame buildings, resting on high plasticity clayey soils strengthened through the coal fly ash column technique, to earthquake motion is investigated. For this aim, the swelling behavior of high plasticity clay soil (CH) is identified with in-situ experimental tests on the regions with high swelling potential in the city of Kirikkale, Turkey. In order to reduce the swelling potential of the investigated regions, the coal fly ash column technique was implemented to the reference soil specimen with high swelling percentage of 15.6%. Experimental results obtained from the strengthened soil specimens were compared to those from the reference specimen. This comparison revealed that the coal fly ash column approach has a considerable effect on improving the swelling behavior of the high plasticity clay soil. The decrease in the volumetric swelling value is also thought to directly improve the response of a building structure settled on high plasticity clay soil. The improvement in the seismic response of existing R/C structures located in the regions with high swelling potential was identified by adopting the increased allowable bearing pressure value of the improved soil in the analyses. Based on the comparative study, structural earthquake response of R/C frame systems was investigated on the basis of the engineering parameters, including the base-shear force, base overturning moment, base axial force and settlement of foundation. The percent changes in these values showed that the base axial force and settlement of foundation were improved with the help of this strengthening application.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66477033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Water inrush generally has a serious impact on karst shallow tunnel construction. Because of in situ fault fracture zone, high degree of weathering and poor quality of rock mass,. karst shallow tunnel would therefore face high risk of water inrush from surface during the disturbance of construction. In addition, the greater the surface water flow would contribute higher probability of water inrush under the same disaster-causing environment. However, existing research has paid less attention to the influence of surface water flow on faults or fissures water inrush. In this study, a risk assessment system of water inrush in karst shallow tunnel with stable surface water supply was firstly proposed on basis of Qinling Water Conveyance Tunnel and the Yuelongmen Tunnel in China. Each indicator was quantified and classified into four risk levels by the attribute mathematics theory and analytic hierarchy process, the degree of confidence criterion was then applied to identify the risk level of the water inrush. The evaluation results were finally verified by actual scenario on site to confirm the validity of this risk assessment system in karst shallow tunnel with stable surface water supply. Accordingly, the proposed method could be popularized and applied in future tunnel projects, because it could provide safe construction reference for karst shallow overburden tunnel with stable surface water supply.
{"title":"Risk assessment of water inrush in karst shallow tunnel with stable surface water supply: Case study","authors":"Zengguang Xu, Meiting Xian, Xiaofeng Li, Wei Zhou, Jiaming Wang, Yaping Wang, J. Chai","doi":"10.12989/GAE.2021.25.6.495","DOIUrl":"https://doi.org/10.12989/GAE.2021.25.6.495","url":null,"abstract":"Water inrush generally has a serious impact on karst shallow tunnel construction. Because of in situ fault fracture zone, high degree of weathering and poor quality of rock mass,. karst shallow tunnel would therefore face high risk of water inrush from surface during the disturbance of construction. In addition, the greater the surface water flow would contribute higher probability of water inrush under the same disaster-causing environment. However, existing research has paid less attention to the influence of surface water flow on faults or fissures water inrush. In this study, a risk assessment system of water inrush in karst shallow tunnel with stable surface water supply was firstly proposed on basis of Qinling Water Conveyance Tunnel and the Yuelongmen Tunnel in China. Each indicator was quantified and classified into four risk levels by the attribute mathematics theory and analytic hierarchy process, the degree of confidence criterion was then applied to identify the risk level of the water inrush. The evaluation results were finally verified by actual scenario on site to confirm the validity of this risk assessment system in karst shallow tunnel with stable surface water supply. Accordingly, the proposed method could be popularized and applied in future tunnel projects, because it could provide safe construction reference for karst shallow overburden tunnel with stable surface water supply.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66477237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.26.3.235
K. Pham, Sangyeong Park, Hangseok Choi, Jongmuk Won
Predicting the frozen zone near the freezing pipe in artificial ground freezing (AGF) is critical in estimating the efficiency of the AGF technique. However, the complexity and uncertainty of many factors affecting the ground temperature cause difficulty in developing a reliable physical model for predicting the ground temperature. This study proposed a data-driven framework to accurately predict the ground temperature during the operation of AGF. Random forest (RF) and extreme gradient boosting (XGB) techniques were employed to develop the prediction model using the dataset of a field experiment in the silty deposit. The developed ensemble models showed relatively good performance (R2 > 0.96), yet the XGB model showed higher accuracy than the RF model. In addition, the evaluated mutual information and importance score revealed that the environmental attributes (ambient temperature, surface temperature, humidity, and wind speed) can be critical in predicting ground temperature during the AFG operation. The prediction models presented in this study can be utilized in evaluating freezing efficiency at the range of geotechnical and environmental attributes.
{"title":"Data-driven framework for predicting ground temperature during ground freezing of a silty deposit","authors":"K. Pham, Sangyeong Park, Hangseok Choi, Jongmuk Won","doi":"10.12989/GAE.2021.26.3.235","DOIUrl":"https://doi.org/10.12989/GAE.2021.26.3.235","url":null,"abstract":"Predicting the frozen zone near the freezing pipe in artificial ground freezing (AGF) is critical in estimating the efficiency of the AGF technique. However, the complexity and uncertainty of many factors affecting the ground temperature cause difficulty in developing a reliable physical model for predicting the ground temperature. This study proposed a data-driven framework to accurately predict the ground temperature during the operation of AGF. Random forest (RF) and extreme gradient boosting (XGB) techniques were employed to develop the prediction model using the dataset of a field experiment in the silty deposit. The developed ensemble models showed relatively good performance (R2 > 0.96), yet the XGB model showed higher accuracy than the RF model. In addition, the evaluated mutual information and importance score revealed that the environmental attributes (ambient temperature, surface temperature, humidity, and wind speed) can be critical in predicting ground temperature during the AFG operation. The prediction models presented in this study can be utilized in evaluating freezing efficiency at the range of geotechnical and environmental attributes.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66478206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.26.4.333
Monideepa Paul, K. Bakshi, R. Sahu
The excess pore pressure increases under undrained cyclic loading which cause decrease in effective stress followed by possible failure in the soft soil. With the inclusion of vertical drains radial drainage allows quick dissipation of excess pressure during cyclic loading and thereby failure of foundation soil may be avoided. The present study aims for analytical closed-form investigation on soft cohesive deposit under radial flow consolidation through vertical drains with no smear when subjected to long-term rapid cyclic loading. The mathematical formulation of pore pressure including degree of consolidation under cyclic loading is developed by using Green
{"title":"An analytical model for radial consolidation prediction under cyclic loading","authors":"Monideepa Paul, K. Bakshi, R. Sahu","doi":"10.12989/GAE.2021.26.4.333","DOIUrl":"https://doi.org/10.12989/GAE.2021.26.4.333","url":null,"abstract":"The excess pore pressure increases under undrained cyclic loading which cause decrease in effective stress followed by possible failure in the soft soil. With the inclusion of vertical drains radial drainage allows quick dissipation of excess pressure during cyclic loading and thereby failure of foundation soil may be avoided. The present study aims for analytical closed-form investigation on soft cohesive deposit under radial flow consolidation through vertical drains with no smear when subjected to long-term rapid cyclic loading. The mathematical formulation of pore pressure including degree of consolidation under cyclic loading is developed by using Green","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66478523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.27.1.031
Jianning Liu, H. Manchao, Hou Shilin, Zhen-chuang Zhu, Yanjun Wang, Jun Yang
The force change characteristics of gravel side support structures during gangue heaping can provide useful information about roadway stability in a new non-pillar-mining approach—noncoal pillar mining with automatically formed gob-side entry (NMAFG). Considering the dynamic shock and static stacking phenomena during gangue heaping, the coefficient of restitution and Janssen model are introduced into the theoretical analysis. Analytical results show that the impact force decreased with increasing gangue heaping height under dynamic shock, while under static stacking, the gangue extrusion force first increased sharply, then increased slowly and stabilized, and the final force was unrelated to the gangue heaping height. Field monitoring was conducted to verify the rationality of the pattern obtained from theoretical analysis. The gangue support structure lateral stress from field monitoring can be divided into two periods. In Period I, the peak value at the lower monitoring point was greater than that at any other point. The lowest sensor was subjected to the greatest impact, at 59.09 kN. In Period II, the stress value first rapidly increased, then slowly increased and stabilized. The final force was unrelated to the gangue height. The sensors at #2 (highest position), #4 (middle position), and #6 (lowest position) measured 31.91 kN, 44.82 kN and 38.19 kN, respectively. The analysis confirmed the variation characteristics of the impact force and extrusion force.
{"title":"Force change of the gravel side support during gangue heaping under a new non-pillar-mining approach","authors":"Jianning Liu, H. Manchao, Hou Shilin, Zhen-chuang Zhu, Yanjun Wang, Jun Yang","doi":"10.12989/GAE.2021.27.1.031","DOIUrl":"https://doi.org/10.12989/GAE.2021.27.1.031","url":null,"abstract":"The force change characteristics of gravel side support structures during gangue heaping can provide useful information about roadway stability in a new non-pillar-mining approach—noncoal pillar mining with automatically formed gob-side entry (NMAFG). Considering the dynamic shock and static stacking phenomena during gangue heaping, the coefficient of restitution and Janssen model are introduced into the theoretical analysis. Analytical results show that the impact force decreased with increasing gangue heaping height under dynamic shock, while under static stacking, the gangue extrusion force first increased sharply, then increased slowly and stabilized, and the final force was unrelated to the gangue heaping height. Field monitoring was conducted to verify the rationality of the pattern obtained from theoretical analysis. The gangue support structure lateral stress from field monitoring can be divided into two periods. In Period I, the peak value at the lower monitoring point was greater than that at any other point. The lowest sensor was subjected to the greatest impact, at 59.09 kN. In Period II, the stress value first rapidly increased, then slowly increased and stabilized. The final force was unrelated to the gangue height. The sensors at #2 (highest position), #4 (middle position), and #6 (lowest position) measured 31.91 kN, 44.82 kN and 38.19 kN, respectively. The analysis confirmed the variation characteristics of the impact force and extrusion force.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66481117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/GAE.2021.27.2.103
Zhanbo Cheng, Xueyu Geng
An environmentally friendly improvement method with using biopolymer stabilization of soil has been currently paid more attention for geotechnical engineering practices. And the existing concerns focused on the performance of biopolymers treated clay due to the occurrence of electrical interaction. Therefore, the effect of biopolymer types and water content on the behaviors of biopolymer-clay mixture should be firstly explored in terms of biopolymer applications. In this study, fall cone tests were conducted to evaluate the consistency variations of eight types of biopolymers treated clay, e.g., carrageenan kappa gum (KG), locust bean gum (LBG), xanthan gum (XG), agar gum (AG), guar gum (GG), sodium alginate (SA), gellan gum (GE) and chitosan (CH) at various biopolymer concentrations (e.g., between 0.1% to 5% biopolymer to soil mass ratio). The results indicated that neutral biopolymers (e.g., LBG and GG) significantly caused the increase of liquid limit and undrained shear strength regardless of biopolymer concentration. And the liquid limit and undrained shear strength of negative charged biopolymers (e.g., KG, SA, GE and XG) treated clay decreased firstly following increased, while AG and CH had limit effect on soil consistency. In addition, the trend of plasticity index was similar to liquid limit altering the USCS classification of biopolymer treated clay as silt or clay. Moreover, empirical equations determining undrained shear strength and shear viscosity of biopolymer-treated clay were also established.
{"title":"Soil consistency and interparticle characteristics of various biopolymer types stabilization of clay","authors":"Zhanbo Cheng, Xueyu Geng","doi":"10.12989/GAE.2021.27.2.103","DOIUrl":"https://doi.org/10.12989/GAE.2021.27.2.103","url":null,"abstract":"An environmentally friendly improvement method with using biopolymer stabilization of soil has been currently paid more attention for geotechnical engineering practices. And the existing concerns focused on the performance of biopolymers treated clay due to the occurrence of electrical interaction. Therefore, the effect of biopolymer types and water content on the behaviors of biopolymer-clay mixture should be firstly explored in terms of biopolymer applications. In this study, fall cone tests were conducted to evaluate the consistency variations of eight types of biopolymers treated clay, e.g., carrageenan kappa gum (KG), locust bean gum (LBG), xanthan gum (XG), agar gum (AG), guar gum (GG), sodium alginate (SA), gellan gum (GE) and chitosan (CH) at various biopolymer concentrations (e.g., between 0.1% to 5% biopolymer to soil mass ratio). The results indicated that neutral biopolymers (e.g., LBG and GG) significantly caused the increase of liquid limit and undrained shear strength regardless of biopolymer concentration. And the liquid limit and undrained shear strength of negative charged biopolymers (e.g., KG, SA, GE and XG) treated clay decreased firstly following increased, while AG and CH had limit effect on soil consistency. In addition, the trend of plasticity index was similar to liquid limit altering the USCS classification of biopolymer treated clay as silt or clay. Moreover, empirical equations determining undrained shear strength and shear viscosity of biopolymer-treated clay were also established.","PeriodicalId":12602,"journal":{"name":"Geomechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66481274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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