Accurately predicting the mechanical behaviour of geological materials is crucial for ensuring the safety of geotechnical structures.However,calibrating advanced models for heterogeneous rocks,such as Copenhagen limes...Accurately predicting the mechanical behaviour of geological materials is crucial for ensuring the safety of geotechnical structures.However,calibrating advanced models for heterogeneous rocks,such as Copenhagen limestone,which exhibits diverse properties due to silicification,cementation,and glaciotectonic fractures,poses significantchallenges.Deterministic approaches often encounter limitations due to data variability and scarcity.Upon embracing a probabilistic approach,recent research emphasises the importance of considering correlations among geotechnical properties to reduce structural variability.This study focuses on the Hoek-Brown(H-B)constitutive model,addressing the challenges of determining parameters,especially with scattered data.The objective is to establish a comprehensive multivariate distribution function encompassing seven pivotal intact rock properties,which are crucial for calibrating the H-B model in the compression zone.Notably,three distinct distribution functions were developed based on the bulk density of intact samples,informed by observed behaviours under triaxial loading(σ_(1)-σ_(3)plane).Rigorous validation using an independent database,including unconfined compressive strength(UCS)and tensile tests,demonstrates the effectiveness of the constructed distributions.The analyses reveal the fundamental role of bulk density through correlations with other parameters.The validated model was employed to back analyse large-scale triaxial tests of layered rock mass samples.The results indicated that under compressive loading,the weakest layer determines the strength and stiffness of the samples when variability within the representative volume is significant.The proposed equivalent rock mass stiffness showed excellent agreement with the observed response.This study establishes a set of probabilistically calibrated H-B multivariate models and provides a practical tool for reliability-based design of underground constructions within Copenhagen limestone.展开更多
基于H-B流变模型和絮网结构理论,构建了考虑时变性的超细全尾砂似膏体流变模型,探究超细全尾砂似膏体长距离管道自流输送过程中的时变特性,推导了相应的管输阻力计算公式.以某深井铁矿质量分数为68%的超细全尾砂似膏体为例,进行了室内...基于H-B流变模型和絮网结构理论,构建了考虑时变性的超细全尾砂似膏体流变模型,探究超细全尾砂似膏体长距离管道自流输送过程中的时变特性,推导了相应的管输阻力计算公式.以某深井铁矿质量分数为68%的超细全尾砂似膏体为例,进行了室内剪切试验和管输阻力计算.结果表明:不同剪切速率下的超细全尾砂似膏体表现出剪切稀化的时变特性,且剪切速率越大,达到平衡状态的时间越短,黏度值越低.在流量为80 m3/h时,管输阻力经225 s降至稳定状态的5.03 M Pa/km,为初始阻力的50.6%.超细全尾砂似膏体长距离自流输送过程中,以稳定状态的阻力损失进行计算更为经济合理.展开更多
文摘Accurately predicting the mechanical behaviour of geological materials is crucial for ensuring the safety of geotechnical structures.However,calibrating advanced models for heterogeneous rocks,such as Copenhagen limestone,which exhibits diverse properties due to silicification,cementation,and glaciotectonic fractures,poses significantchallenges.Deterministic approaches often encounter limitations due to data variability and scarcity.Upon embracing a probabilistic approach,recent research emphasises the importance of considering correlations among geotechnical properties to reduce structural variability.This study focuses on the Hoek-Brown(H-B)constitutive model,addressing the challenges of determining parameters,especially with scattered data.The objective is to establish a comprehensive multivariate distribution function encompassing seven pivotal intact rock properties,which are crucial for calibrating the H-B model in the compression zone.Notably,three distinct distribution functions were developed based on the bulk density of intact samples,informed by observed behaviours under triaxial loading(σ_(1)-σ_(3)plane).Rigorous validation using an independent database,including unconfined compressive strength(UCS)and tensile tests,demonstrates the effectiveness of the constructed distributions.The analyses reveal the fundamental role of bulk density through correlations with other parameters.The validated model was employed to back analyse large-scale triaxial tests of layered rock mass samples.The results indicated that under compressive loading,the weakest layer determines the strength and stiffness of the samples when variability within the representative volume is significant.The proposed equivalent rock mass stiffness showed excellent agreement with the observed response.This study establishes a set of probabilistically calibrated H-B multivariate models and provides a practical tool for reliability-based design of underground constructions within Copenhagen limestone.
文摘基于H-B流变模型和絮网结构理论,构建了考虑时变性的超细全尾砂似膏体流变模型,探究超细全尾砂似膏体长距离管道自流输送过程中的时变特性,推导了相应的管输阻力计算公式.以某深井铁矿质量分数为68%的超细全尾砂似膏体为例,进行了室内剪切试验和管输阻力计算.结果表明:不同剪切速率下的超细全尾砂似膏体表现出剪切稀化的时变特性,且剪切速率越大,达到平衡状态的时间越短,黏度值越低.在流量为80 m3/h时,管输阻力经225 s降至稳定状态的5.03 M Pa/km,为初始阻力的50.6%.超细全尾砂似膏体长距离自流输送过程中,以稳定状态的阻力损失进行计算更为经济合理.
