In this study,application of the spectral representation method for generation of endurance time excitation functions is introduced.Using this method,the intensifying acceleration time series is generated so that its ...In this study,application of the spectral representation method for generation of endurance time excitation functions is introduced.Using this method,the intensifying acceleration time series is generated so that its acceleration response spectrum in any desired time duration is compatible with a time-scaled predefined acceleration response spectrum.For this purpose,simulated stationary acceleration time series is multiplied by the time dependent linear modulation function,then using a simple iterative scheme,it is forced to match a target acceleration response spectrum.It is shown that the generated samples have excellent conformity in low frequency,which is useful for nonlinear endurance time analysis.In the second part of this study,it is shown that this procedure can be extended to generate a set of spatially correlated endurance time excitation functions.This makes it possible to assess the performance of long structures under multi-support seismic excitation using endurance time analysis.展开更多
Circumferential yielding lining is able to tolerate controlled displacements without failure,which has been proven to be an effective solution to large deformation problem in squeezing tunnels.However,up to now,there ...Circumferential yielding lining is able to tolerate controlled displacements without failure,which has been proven to be an effective solution to large deformation problem in squeezing tunnels.However,up to now,there has not been a well-established design method for it.This paper aims to present a detailed analytical computation of support characteristic curve(SCC)for circumferential yielding lining,which is a significant aspect of the implementation of convergence-confinement method(CCM)in tunnel support design.Circumferential yielding lining consists of segmental shotcrete linings and highly deformable elements,and its superior performance mainly depends on the mechanical characteristic of highly deformable element.The deformation behavior of highly deformable element is firstly investigated.Its whole deforming process can be divided into three stages including elastic,yielding and compaction stages.Especially in the compaction stage of highly deformable element,a nonlinear stress-strain relationship can be observed.For mathematical convenience,the stress-strain curve in this period is processed as several linear sub-curves.Then,the reasons for closure of circumferential yielding lining in different stages are explained,and the corresponding accurate equations required for constructing the SCC are provided.Furthermore,this paper carries out two case studies illustrating the application of all equations needed to construct the SCC for circumferential yielding lining,where the reliability and feasibility of theoretical derivation are also well verified.Finally,this paper discusses the sensitivity of sub-division in element compaction stage and the influence of element length on SCC.The outcome of this paper could be used in the design of proper circumferential yielding lining.展开更多
文摘In this study,application of the spectral representation method for generation of endurance time excitation functions is introduced.Using this method,the intensifying acceleration time series is generated so that its acceleration response spectrum in any desired time duration is compatible with a time-scaled predefined acceleration response spectrum.For this purpose,simulated stationary acceleration time series is multiplied by the time dependent linear modulation function,then using a simple iterative scheme,it is forced to match a target acceleration response spectrum.It is shown that the generated samples have excellent conformity in low frequency,which is useful for nonlinear endurance time analysis.In the second part of this study,it is shown that this procedure can be extended to generate a set of spatially correlated endurance time excitation functions.This makes it possible to assess the performance of long structures under multi-support seismic excitation using endurance time analysis.
基金supported by National Natural Science Foundation of China(Grant Nos.11872287 and 51908431)Fund of Shaanxi Key Research and Development Program(Grant No.2019ZDLGY01-10)。
文摘Circumferential yielding lining is able to tolerate controlled displacements without failure,which has been proven to be an effective solution to large deformation problem in squeezing tunnels.However,up to now,there has not been a well-established design method for it.This paper aims to present a detailed analytical computation of support characteristic curve(SCC)for circumferential yielding lining,which is a significant aspect of the implementation of convergence-confinement method(CCM)in tunnel support design.Circumferential yielding lining consists of segmental shotcrete linings and highly deformable elements,and its superior performance mainly depends on the mechanical characteristic of highly deformable element.The deformation behavior of highly deformable element is firstly investigated.Its whole deforming process can be divided into three stages including elastic,yielding and compaction stages.Especially in the compaction stage of highly deformable element,a nonlinear stress-strain relationship can be observed.For mathematical convenience,the stress-strain curve in this period is processed as several linear sub-curves.Then,the reasons for closure of circumferential yielding lining in different stages are explained,and the corresponding accurate equations required for constructing the SCC are provided.Furthermore,this paper carries out two case studies illustrating the application of all equations needed to construct the SCC for circumferential yielding lining,where the reliability and feasibility of theoretical derivation are also well verified.Finally,this paper discusses the sensitivity of sub-division in element compaction stage and the influence of element length on SCC.The outcome of this paper could be used in the design of proper circumferential yielding lining.
