We have developed a novel rheo-optical measurement system based on two-dimensional polarization analysis, which can evaluate the rheological properties and structure of a complex fluid simultaneously. To assess the utility of the system, we used it to investigate the relationship between yield behavior and structural evolution in a TEMPO-oxidized cellulose nanofiber (T-CNF) suspension, which is a yield-stress fluid that has been actively studied in recent years. To analyze the structural evolution of a T-CNF suspension, stress-ramp tests were conducted. A two-step yield behavior was observed, and distributions of retardation and orientation axis varied dramatically with increasing shear stress. In particular, different distributions were observed in the three regions: after the first yield point, before the second yield point, and after the second yield point. In experiments with a low-concentration T-CNF suspension that exhibits no yield behavior, the retardation increased monotonically with increasing shear stress, and its distribution was uniform. It was demonstrated that the yield behavior and related structures can be analyzed from these results. More detailed structural mechanisms require various rheological tests using the developed system. However, the present insights demonstrate the valuable information provided by the developed rheo-optical measurement system, contributing essential knowledge for applications in various fields.
我们开发了一种基于二维偏振分析的新型流变光学测量系统，可以同时评估复杂流体的流变特性和结构。为了评估该系统的实用性，我们用它来研究 TEMPO 氧化纤维素纳米纤维（T-CNF）悬浮液中屈服行为与结构演变之间的关系。为了分析 T-CNF 悬浮液的结构演变，我们进行了应力斜坡试验。试验观察到了两步屈服行为，随着剪切应力的增加，延迟和取向轴的分布也发生了显著变化。特别是在三个区域观察到了不同的分布：第一个屈服点之后、第二个屈服点之前和第二个屈服点之后。在使用低浓度 T-CNF 悬浮液进行的实验中，该悬浮液没有屈服行为，其延迟率随剪切应力的增加而单调增加，且分布均匀。实验证明，可以从这些结果中分析屈服行为和相关结构。更详细的结构机制需要使用所开发的系统进行各种流变测试。不过，目前的研究结果表明，所开发的流变光学测量系统提供了宝贵的信息，为各个领域的应用提供了必要的知识。
{"title":"Two-dimensional rheo-optical measurement system to study dynamics and structure of complex fluids","authors":"Taisuke Sato, Yoshifumi Yamagata, Yasunori Sato, Takashi Onuma, Keisuke Miyamoto, Tsutomu Takahashi","doi":"10.1515/arh-2024-0006","DOIUrl":"https://doi.org/10.1515/arh-2024-0006","url":null,"abstract":"We have developed a novel rheo-optical measurement system based on two-dimensional polarization analysis, which can evaluate the rheological properties and structure of a complex fluid simultaneously. To assess the utility of the system, we used it to investigate the relationship between yield behavior and structural evolution in a TEMPO-oxidized cellulose nanofiber (T-CNF) suspension, which is a yield-stress fluid that has been actively studied in recent years. To analyze the structural evolution of a T-CNF suspension, stress-ramp tests were conducted. A two-step yield behavior was observed, and distributions of retardation and orientation axis varied dramatically with increasing shear stress. In particular, different distributions were observed in the three regions: after the first yield point, before the second yield point, and after the second yield point. In experiments with a low-concentration T-CNF suspension that exhibits no yield behavior, the retardation increased monotonically with increasing shear stress, and its distribution was uniform. It was demonstrated that the yield behavior and related structures can be analyzed from these results. More detailed structural mechanisms require various rheological tests using the developed system. However, the present insights demonstrate the valuable information provided by the developed rheo-optical measurement system, contributing essential knowledge for applications in various fields.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"197 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140939770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study conducted a series of true triaxial hydraulic fracturing experiments on Longmaxi Formation shale. We investigated the interaction between internal factors and external factors on the inter-well interference of 400 mm cubic porous specimens. During dual wellbore fracturing at different formations, forming inter-well interference through secondary hydraulic fractures lead to a lower interference intensity and larger stimulated rock area. When adopting a three-layer well layout during three-wellbore fracturing, the vertical distance between the wells is shortened, activating more bedding planes. Regardless of a horizontal well placement with two wellbores or a three-dimensional two-layer well placement with three wellbores, increasing the vertical stress leads to more potent inter-well interference. There is no absolute positive correlation between the stimulated rock area and inter-well interference. It can be influenced by the presence of natural fractures within the formation that can even lead to a reduction in the stimulated area. When the well placement changes from two horizontal wellbores to three-dimensional two-layer sites with three wellbores and the vertical stress increases, the inter-well interference becomes stronger, but the stimulated rock area only increases by 22.6%. These findings provide crucial guidance for the hydraulic fracturing design of shale reservoirs.
{"title":"Shale hydraulic fracture morphology and inter-well interference rule under multi-wellbore test","authors":"Yulin Ma, Yupeng Du, Dandan Lu","doi":"10.1515/arh-2024-0005","DOIUrl":"https://doi.org/10.1515/arh-2024-0005","url":null,"abstract":"This study conducted a series of true triaxial hydraulic fracturing experiments on Longmaxi Formation shale. We investigated the interaction between internal factors and external factors on the inter-well interference of 400 mm cubic porous specimens. During dual wellbore fracturing at different formations, forming inter-well interference through secondary hydraulic fractures lead to a lower interference intensity and larger stimulated rock area. When adopting a three-layer well layout during three-wellbore fracturing, the vertical distance between the wells is shortened, activating more bedding planes. Regardless of a horizontal well placement with two wellbores or a three-dimensional two-layer well placement with three wellbores, increasing the vertical stress leads to more potent inter-well interference. There is no absolute positive correlation between the stimulated rock area and inter-well interference. It can be influenced by the presence of natural fractures within the formation that can even lead to a reduction in the stimulated area. When the well placement changes from two horizontal wellbores to three-dimensional two-layer sites with three wellbores and the vertical stress increases, the inter-well interference becomes stronger, but the stimulated rock area only increases by 22.6%. These findings provide crucial guidance for the hydraulic fracturing design of shale reservoirs.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"25 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140800033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work presents a viscosity model based on the Giesekus equation. The model is shown to be more flexible than the Cross and Carreau models in representing the shear-thinning behavior of viscoelastic fluids. It has been investigated that the influence of the model parameters on the viscosity showed that the mobility parameter α plays a distinctive role in adjusting the inflection shape of the viscosity curve. The results show that the new model is able to accurately capture the shear-thinning behavior of polystyrene data, while the Cross and Carreau models tend to underestimate and overestimate the viscosity at the inflection point, respectively. It has been also shown that the Yasuda-type modification is also applicable to the proposed model. Moreover, the viscosity model has been applied to simultaneously fitting a polymeric liquid system and a particulate slurry system. The new viscosity model is a promising tool for modeling the shear-thinning behavior of viscoelastic fluids in a wide range of applications.
{"title":"Viscosity model based on Giesekus equation","authors":"Sun Kyoung Kim","doi":"10.1515/arh-2024-0004","DOIUrl":"https://doi.org/10.1515/arh-2024-0004","url":null,"abstract":"This work presents a viscosity model based on the Giesekus equation. The model is shown to be more flexible than the Cross and Carreau models in representing the shear-thinning behavior of viscoelastic fluids. It has been investigated that the influence of the model parameters on the viscosity showed that the mobility parameter <jats:italic>α</jats:italic> plays a distinctive role in adjusting the inflection shape of the viscosity curve. The results show that the new model is able to accurately capture the shear-thinning behavior of polystyrene data, while the Cross and Carreau models tend to underestimate and overestimate the viscosity at the inflection point, respectively. It has been also shown that the Yasuda-type modification is also applicable to the proposed model. Moreover, the viscosity model has been applied to simultaneously fitting a polymeric liquid system and a particulate slurry system. The new viscosity model is a promising tool for modeling the shear-thinning behavior of viscoelastic fluids in a wide range of applications.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"19 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140799993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gang Huang, Gang Lu, Ji Zhang, Fengjun Zhou, Dongwei Li
Stress path change has a great relationship with the effect of deformation and strength of rock. However, the underground rock body is in the engineering environment where the stress field, seepage field, and other fields are coupled to change, the law of fluid flow in the rock body is complex and variable. The change in the stress field has an important effect on the seepage characteristics of rock body; therefore, it is necessary to study the pattern of rock permeability evolution pattern by different stress paths. This study is based on the study of limestone, conducting triaxial unloading seepage mechanics experiments, the evolution of permeability properties of limestone specimens was analyzed based on the test results. The results show that in the conventional triaxial loading seepage test, the permeability of the limestone decreases before the rock stress reaches the peak intensity and increases after that. Increasing axial pressure unloading surrounding pressure compression section, permeability loss rate and effective stress are in line with the changing law of Gaussian distribution function. Under the action of constant axial pressure unloading surrounding pressure, with the increase in unloading amount, the permeability rate of change appears to increase slowly, and in the late stage of unloading section, the permeability rate of change appears to surge. Unloading section permeability change rate and cumulative unloading amount are in line with the law of change of the exponential function. Creep unloading pressure seepage test found that unloading pressure stage strain-time and permeability-time evolution characteristics are in line with the exponential rule of change. The experimental results of this study can provide an important experimental and theoretical basis for the permeability analysis of low-permeability rock body under complex stress conditions in underground engineering.
{"title":"Study on the evolution of permeability properties of limestone under different stress paths","authors":"Gang Huang, Gang Lu, Ji Zhang, Fengjun Zhou, Dongwei Li","doi":"10.1515/arh-2024-0003","DOIUrl":"https://doi.org/10.1515/arh-2024-0003","url":null,"abstract":"Stress path change has a great relationship with the effect of deformation and strength of rock. However, the underground rock body is in the engineering environment where the stress field, seepage field, and other fields are coupled to change, the law of fluid flow in the rock body is complex and variable. The change in the stress field has an important effect on the seepage characteristics of rock body; therefore, it is necessary to study the pattern of rock permeability evolution pattern by different stress paths. This study is based on the study of limestone, conducting triaxial unloading seepage mechanics experiments, the evolution of permeability properties of limestone specimens was analyzed based on the test results. The results show that in the conventional triaxial loading seepage test, the permeability of the limestone decreases before the rock stress reaches the peak intensity and increases after that. Increasing axial pressure unloading surrounding pressure compression section, permeability loss rate and effective stress are in line with the changing law of Gaussian distribution function. Under the action of constant axial pressure unloading surrounding pressure, with the increase in unloading amount, the permeability rate of change appears to increase slowly, and in the late stage of unloading section, the permeability rate of change appears to surge. Unloading section permeability change rate and cumulative unloading amount are in line with the law of change of the exponential function. Creep unloading pressure seepage test found that unloading pressure stage strain-time and permeability-time evolution characteristics are in line with the exponential rule of change. The experimental results of this study can provide an important experimental and theoretical basis for the permeability analysis of low-permeability rock body under complex stress conditions in underground engineering.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"4 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The performance of bituminous materials is often evaluated using rheological properties measured within the linear viscoelastic region. If there is a univocal temperature dependence of all the relaxation times, data obtained in different operating conditions can be translated onto a logarithmic scale where they partially overlap and merge into a single master curve. This is the well-known time–temperature superposition principle that has been successfully applied for decades. However, the empirical nature of the method has led to many different procedures being used for the graphical construction of the master curve. In addition, the continuously increasing calculating power has led to new approaches, such as the simultaneous modelling of the represented viscoelastic function. Losing track of the basic statements of the method is the hidden drawback of this wide range of available protocols with the risk of artefacts and incongruences being introduced in the construction of the master curves. This review summarizes these basic statements together with the empirical and phenomenological approaches developed over the years. The aim of this study is to help the reader in choosing the most appropriate method to build the master curves. Although the subject of the review is of general application, the field of bitumen is focused on.
{"title":"Master curves construction for viscoelastic functions of bituminous materials","authors":"Giovanni Polacco, Sara Filippi","doi":"10.1515/arh-2023-0117","DOIUrl":"https://doi.org/10.1515/arh-2023-0117","url":null,"abstract":"The performance of bituminous materials is often evaluated using rheological properties measured within the linear viscoelastic region. If there is a univocal temperature dependence of all the relaxation times, data obtained in different operating conditions can be translated onto a logarithmic scale where they partially overlap and merge into a single master curve. This is the well-known time–temperature superposition principle that has been successfully applied for decades. However, the empirical nature of the method has led to many different procedures being used for the graphical construction of the master curve. In addition, the continuously increasing calculating power has led to new approaches, such as the simultaneous modelling of the represented viscoelastic function. Losing track of the basic statements of the method is the hidden drawback of this wide range of available protocols with the risk of artefacts and incongruences being introduced in the construction of the master curves. This review summarizes these basic statements together with the empirical and phenomenological approaches developed over the years. The aim of this study is to help the reader in choosing the most appropriate method to build the master curves. Although the subject of the review is of general application, the field of bitumen is focused on.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"35 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140156254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Changes in the stress field and seepage field of mining unloading are one of the important causes of deformation and destabilization of the rock body of the bottom slab. With the increase of mining intensity and depth, the disaster of water influx on the bottom plate under the dual action of mining unloading and pressurized water has become one of the main problems restricting the efficient and safe mining of coal. Based on the research background of confined water inrush from Ordovician limestone floor in North China Coalfield, the numerical analysis revealed that mining unloading concentrates stresses, increases deformation, and increases the plastic zone and permeability range. Based on laboratory acoustic emission and mechanical tests, it is found that the peak of acoustic emission ringing number can be one of the precursor information of limestone seepage mutation. This study reveals the evolution law of rock body deformation and permeability under the unloading path, and the research obtains the unloading seepage and water gushing disaster mechanism of the subgrade rock body.
{"title":"Study on precursor information and disaster mechanism of sudden change of seepage in mining rock mass","authors":"Yijun Gao, Zongjie Zhu, Zhiming Liu, Gang Huang","doi":"10.1515/arh-2023-0116","DOIUrl":"https://doi.org/10.1515/arh-2023-0116","url":null,"abstract":"Changes in the stress field and seepage field of mining unloading are one of the important causes of deformation and destabilization of the rock body of the bottom slab. With the increase of mining intensity and depth, the disaster of water influx on the bottom plate under the dual action of mining unloading and pressurized water has become one of the main problems restricting the efficient and safe mining of coal. Based on the research background of confined water inrush from Ordovician limestone floor in North China Coalfield, the numerical analysis revealed that mining unloading concentrates stresses, increases deformation, and increases the plastic zone and permeability range. Based on laboratory acoustic emission and mechanical tests, it is found that the peak of acoustic emission ringing number can be one of the precursor information of limestone seepage mutation. This study reveals the evolution law of rock body deformation and permeability under the unloading path, and the research obtains the unloading seepage and water gushing disaster mechanism of the subgrade rock body.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"170 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140010242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Minghong Sheng, Fangqing Lu, Nan Jiang, Panpan Guo, Xian Li, Ran An, Yixian Wang
The presence of karst formations significantly impacts the load-bearing capacity of pile foundations in karst geological environments, posing a challenge to their design. This study investigated the bearing characteristics of karst pile foundations using the physical model test and numerical analysis. First, the influence of cave height and span on the bearing capacity of pile foundations is examined using model tests. The results demonstrate that the height of karst caves greatly affects the bearing capacity of karst pile foundations. Subsequently, numerical analysis further explores the bearing characteristics of these foundations. It reveals that as the top load on pile increases, an arch-shaped tensile damage zone forms at the top of karst cave and gradually expands. The rock failure in this area leads to a decrease in adhesion between rock strata and pile foundation, consequently reducing its load-bearing capacity. Finally, experimental results are compared with numerical results to validate consistency and mutual verifiability between physical model tests and numerical analyses. The outcomes of the research provide valuable insights for designing rock-socketed pile foundations in similar karst areas.
{"title":"Bearing behavior of pile foundation in karst region: Physical model test and finite element analysis","authors":"Minghong Sheng, Fangqing Lu, Nan Jiang, Panpan Guo, Xian Li, Ran An, Yixian Wang","doi":"10.1515/arh-2023-0115","DOIUrl":"https://doi.org/10.1515/arh-2023-0115","url":null,"abstract":"The presence of karst formations significantly impacts the load-bearing capacity of pile foundations in karst geological environments, posing a challenge to their design. This study investigated the bearing characteristics of karst pile foundations using the physical model test and numerical analysis. First, the influence of cave height and span on the bearing capacity of pile foundations is examined using model tests. The results demonstrate that the height of karst caves greatly affects the bearing capacity of karst pile foundations. Subsequently, numerical analysis further explores the bearing characteristics of these foundations. It reveals that as the top load on pile increases, an arch-shaped tensile damage zone forms at the top of karst cave and gradually expands. The rock failure in this area leads to a decrease in adhesion between rock strata and pile foundation, consequently reducing its load-bearing capacity. Finally, experimental results are compared with numerical results to validate consistency and mutual verifiability between physical model tests and numerical analyses. The outcomes of the research provide valuable insights for designing rock-socketed pile foundations in similar karst areas.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"48 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139950177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The distribution of stress and the normal extrusion load threshold in weak interlayer are crucial for direct shear test of filled rock joints, but there is a lack of theoretical research in this area. First, an analytical solution for stress distribution was derived using a semi-inverse method. Then, it is compared by the numerical simulation method. Finally, the influence of the width and thickness of weak interlayer on the extreme values of stress components was analyzed, and the distribution pattern of the normal extrusion load was discussed. The results show that under the same conditions, the analytical solution and the numerical simulation results are in good agreement. The maximum horizontal stress in the weak interlayer decreases with increasing width and increases with increasing thickness, while the change of the minimum is opposite. The normal extrusion load increases first and then decreases along the width direction of the weak interlayer. By comparing the normal extrusion load with the empirical value, the mechanism of extrusion failure in the weak interlayer is revealed.
{"title":"Study on stress distribution and extrusion load threshold of compressed filled rock joints","authors":"Pengpeng Wang, Shigui Du, Gan Li, Zhanyou Luo","doi":"10.1515/arh-2023-0113","DOIUrl":"https://doi.org/10.1515/arh-2023-0113","url":null,"abstract":"The distribution of stress and the normal extrusion load threshold in weak interlayer are crucial for direct shear test of filled rock joints, but there is a lack of theoretical research in this area. First, an analytical solution for stress distribution was derived using a semi-inverse method. Then, it is compared by the numerical simulation method. Finally, the influence of the width and thickness of weak interlayer on the extreme values of stress components was analyzed, and the distribution pattern of the normal extrusion load was discussed. The results show that under the same conditions, the analytical solution and the numerical simulation results are in good agreement. The maximum horizontal stress in the weak interlayer decreases with increasing width and increases with increasing thickness, while the change of the minimum is opposite. The normal extrusion load increases first and then decreases along the width direction of the weak interlayer. By comparing the normal extrusion load with the empirical value, the mechanism of extrusion failure in the weak interlayer is revealed.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"3 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139552307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roughness and inclination are important factors affecting the strength and deformation properties of jointed rock masses. Serrated joint specimens with varying joint roughness coefficient (JRC) and inclination angle were manufactured by 3D printing technique and cement mortar material. Then, uniaxial compression tests were performed for serrated joint specimens. The results show that when inclination angle equals 0° or 90°, the stress–strain curves of serrated joint specimens with various JRC values are basically the same and display a similar variation trend as that of the complete specimen, hence JRC presents a very little impact. When inclination angle varies from 30° to 60°, the stress–strain curves display a significant difference for various JRC values. Both the compressive strength and peak strain increase with the JRC value. With the increase in JRC value, the stress–strain curve exhibits a stress drop point, and with the further increase in JRC value, the stress drop point obviously delays or disappears directly. Variation in uniaxial compressive strength and deformation modulus with inclination angle is approximately U-shape for serrated joint specimens and displays typical anisotropic characteristics. Due to the variation in inclination angles and JRC values, failure modes of serrated joint specimens under uniaxial compression varies from splitting tensile or shear slip failure to compound tensile and shear failure. Rough serrated joint has a strengthening effect on the resistance ability to vertical load, and large roughness can effectively slow down the shear slip failure of jointed rock masses.
{"title":"Experimental study of uniaxial compressive mechanical properties of rough jointed rock masses based on 3D printing","authors":"Pu Yuan, Aobo Li, Changning Chen, Xuefeng Lu","doi":"10.1515/arh-2023-0114","DOIUrl":"https://doi.org/10.1515/arh-2023-0114","url":null,"abstract":"Roughness and inclination are important factors affecting the strength and deformation properties of jointed rock masses. Serrated joint specimens with varying joint roughness coefficient (JRC) and inclination angle were manufactured by 3D printing technique and cement mortar material. Then, uniaxial compression tests were performed for serrated joint specimens. The results show that when inclination angle equals 0° or 90°, the stress–strain curves of serrated joint specimens with various JRC values are basically the same and display a similar variation trend as that of the complete specimen, hence JRC presents a very little impact. When inclination angle varies from 30° to 60°, the stress–strain curves display a significant difference for various JRC values. Both the compressive strength and peak strain increase with the JRC value. With the increase in JRC value, the stress–strain curve exhibits a stress drop point, and with the further increase in JRC value, the stress drop point obviously delays or disappears directly. Variation in uniaxial compressive strength and deformation modulus with inclination angle is approximately U-shape for serrated joint specimens and displays typical anisotropic characteristics. Due to the variation in inclination angles and JRC values, failure modes of serrated joint specimens under uniaxial compression varies from splitting tensile or shear slip failure to compound tensile and shear failure. Rough serrated joint has a strengthening effect on the resistance ability to vertical load, and large roughness can effectively slow down the shear slip failure of jointed rock masses.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"23 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139105369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiang Liu, Yanlin Zhao, Jian Liao, Tao Tan, Xiaguang Wang, Yang Li, Zhe Tan
To study the mechanical properties of saturated sandstone, experiments were conducted under hydro-mechanical coupling on saturated sandstone. A damage constitutive model was established to describe the response of saturated sandstone under pore pressure, and its validity was verified using the results of the triaxial tests. The results indicate that the peak strength (σp), effective peak strength (σp′), residual strength (σr), effective normal stress (σn′), effective shear strength (τn′), elasticity modulus (E), and rupture angle (θ) of sandstone are positively correlated with the confining pressure (σ3) and negatively correlated with the pore pressure (P). Conversely, Poisson’s ratio (μ) exhibits an opposite relationship. The model parameters exhibit non-linear relationships with the confining pressure (σ3), with the parameter m decreasing gradually as the confining pressure increases, and the parameter F0 increasing with higher confining pressure (σ3). Moreover, the pore pressure (P) and the confining pressure (σ3) significantly affect the damage variables (D), with the stress value at the damage initiation point increasing with increasing confining pressure (σ3), while the strain value at the damage initiation point decreasing with increasing pore pressure (P), indicating that pore pressure induces damage development in rocks.
为了研究饱和砂岩的力学特性，对饱和砂岩进行了水力机械耦合试验。建立了一个描述饱和砂岩在孔隙压力下响应的破坏组成模型，并利用三轴试验结果验证了该模型的有效性。结果表明，砂岩的峰值强度（σ p）、有效峰值强度（σ p′）、残余强度（σ r）、有效法向应力（σ n′）、有效剪切强度（τ n′）、弹性模量（E）和断裂角（θ）与约束压力（σ 3）呈正相关，与孔隙压力（P）呈负相关。相反，泊松比 (μ) 则表现出相反的关系。模型参数与封闭压力（σ 3）呈非线性关系，随着封闭压力的增加，参数 m 逐渐减小，而参数 F 0 则随着封闭压力（σ 3）的增加而增大。此外，孔隙压力（P）和约束压力（σ 3）对破坏变量（D）有显著影响，破坏起始点的应力值随着约束压力（σ 3）的增大而增大，而破坏起始点的应变值随着孔隙压力（P）的增大而减小，表明孔隙压力诱导岩石的破坏发展。
{"title":"Strength characteristics and damage constitutive model of sandstone under hydro-mechanical coupling","authors":"Qiang Liu, Yanlin Zhao, Jian Liao, Tao Tan, Xiaguang Wang, Yang Li, Zhe Tan","doi":"10.1515/arh-2023-0112","DOIUrl":"https://doi.org/10.1515/arh-2023-0112","url":null,"abstract":"To study the mechanical properties of saturated sandstone, experiments were conducted under hydro-mechanical coupling on saturated sandstone. A damage constitutive model was established to describe the response of saturated sandstone under pore pressure, and its validity was verified using the results of the triaxial tests. The results indicate that the peak strength (<jats:italic>σ</jats:italic> <jats:sub>p</jats:sub>), effective peak strength (<jats:italic>σ</jats:italic> <jats:sub>p</jats:sub>′), residual strength (<jats:italic>σ</jats:italic> <jats:sub>r</jats:sub>), effective normal stress (<jats:italic>σ</jats:italic> <jats:sub>n</jats:sub>′), effective shear strength (<jats:italic>τ</jats:italic> <jats:sub>n</jats:sub>′), elasticity modulus (<jats:italic>E</jats:italic>), and rupture angle (<jats:italic>θ</jats:italic>) of sandstone are positively correlated with the confining pressure (<jats:italic>σ</jats:italic> <jats:sub>3</jats:sub>) and negatively correlated with the pore pressure (<jats:italic>P</jats:italic>). Conversely, Poisson’s ratio (<jats:italic>μ</jats:italic>) exhibits an opposite relationship. The model parameters exhibit non-linear relationships with the confining pressure (<jats:italic>σ</jats:italic> <jats:sub>3</jats:sub>), with the parameter <jats:italic>m</jats:italic> decreasing gradually as the confining pressure increases, and the parameter <jats:italic>F</jats:italic> <jats:sub>0</jats:sub> increasing with higher confining pressure (<jats:italic>σ</jats:italic> <jats:sub>3</jats:sub>). Moreover, the pore pressure (<jats:italic>P</jats:italic>) and the confining pressure (<jats:italic>σ</jats:italic> <jats:sub>3</jats:sub>) significantly affect the damage variables (<jats:italic>D</jats:italic>), with the stress value at the damage initiation point increasing with increasing confining pressure (<jats:italic>σ</jats:italic> <jats:sub>3</jats:sub>), while the strain value at the damage initiation point decreasing with increasing pore pressure (<jats:italic>P</jats:italic>), indicating that pore pressure induces damage development in rocks.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"87 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138687897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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