The subsidence prediction theory under the condition of grouting into bedseparated was developed. Reducing ground subsidence by grouting was carried out on eight fully-mechanized top-coal caving faces, by using the co...The subsidence prediction theory under the condition of grouting into bedseparated was developed. Reducing ground subsidence by grouting was carried out on eight fully-mechanized top-coal caving faces, by using the continuous grouting in multiple-layer to obtain experiment results of reducing subsidence under fully mining. The similar material model that can be dismantled under the condition of constant temperature and constant humidity was developed. The model was used to simulate the evolution of overburden bed-separated under such constraints of temperature and humidity, at the same time, and to test the hardening process of similar materials.展开更多
The seismic performance of a fully fabricated bridge is a key factor limiting its application.In this study,a fiber element model of a fabricated concrete pier with grouting sleeve-prestressed tendon composite connect...The seismic performance of a fully fabricated bridge is a key factor limiting its application.In this study,a fiber element model of a fabricated concrete pier with grouting sleeve-prestressed tendon composite connections was built and verified.A numerical analysis of three types of continuous girder bridges was conducted with different piers:a cast-in-place reinforced concrete pier,a grouting sleeve-fabricated pier,and a grouting sleeve-prestressed tendon composite fabricated pier.Furthermore,the seismic performance of the composite fabricated pier was investigated.The results show that the OpenSees fiber element model can successfully simulate the hysteresis behavior and failure mode of the grouted sleeve-fabricated pier.Under traditional non-near-fault ground motions,the pier top displacements of the grouting sleeve-fabricated pier and the composite fabricated pier were less than those of the cast-in-place reinforced concrete pier.The composite fabricated pier had a good self-centering capability.In addition,the plastic hinge zones of the grouting sleeve-fabricated pier and the composite fabricated pier shifted to the joint seam and upper edge of the grouting sleeve,respectively.The composite fabricated pier with optimal design parameters has good seismic performance and can be applied in high-intensity seismic areas;however,the influence of pile-soil interaction on its seismic performance should not be ignored.展开更多
In the new tunnel under close distance through the existing tunnel risk source,the grouting scheme developed to compensate for stratum losses is still based on empirical methods,relying on the overburden thickness of ...In the new tunnel under close distance through the existing tunnel risk source,the grouting scheme developed to compensate for stratum losses is still based on empirical methods,relying on the overburden thickness of existing tunnels.This can potentially lead to an excessively high or low probability of uplift of existing tunnels.Proposing a coupled deformation analysis method between the grouting construction and adjacent existing tunnels is of great theoretical significance for developing grouting schemes.In order to reasonably limit the design parameters of grouting construction,based on the theory of fluid–solid coupling elastic pore-column expansion and the theory of random media,the calculation method of stratum displacement which simultaneously considers the coexistence of grout compaction expansion and permeability diffusion mode is derived,and the accuracy of the calculation method is verified by engineering examples.The accuracy of this calculation method was verified through engineering examples.Combined with the deformation coordination condition,the existing tunnel is regarded as an elastic Euler-Bernoulli continuous beam,and the finite element coupling balance equation of the interaction between the existing tunnel and the surrounding soil is obtained.Based on this,a coupling calculation model of the grouting construction and the deformation response of the adjacent existing tunnel is established.Combined with three times of grouting construction examples in the shield tunneling project of Beijing Metro Line 12 under the existing airport line,the reliability of the coupling calculation model to determine the grouting construction parameters is verified.The calculation parameters in the coupling calculation model have clear physical meanings,which can provide a theoretical basis for the grouting design of similar risk source projects.展开更多
基金Supported by National Natural Science Foundation of China（50174035） National Key Project of Scientific and Technical Supporting Programs（2006BAB16B00） National.＂973＂ Program（2006CB202200）
文摘The subsidence prediction theory under the condition of grouting into bedseparated was developed. Reducing ground subsidence by grouting was carried out on eight fully-mechanized top-coal caving faces, by using the continuous grouting in multiple-layer to obtain experiment results of reducing subsidence under fully mining. The similar material model that can be dismantled under the condition of constant temperature and constant humidity was developed. The model was used to simulate the evolution of overburden bed-separated under such constraints of temperature and humidity, at the same time, and to test the hardening process of similar materials.
基金This study was supported by the National Natural Science Foundation of China(Grant Nos.52108428,52178446,51978021,and 51908015)the Fundamental Research Funds for the Central Universities(No.2023MS067).We gratefully acknowledge their support.
文摘The seismic performance of a fully fabricated bridge is a key factor limiting its application.In this study,a fiber element model of a fabricated concrete pier with grouting sleeve-prestressed tendon composite connections was built and verified.A numerical analysis of three types of continuous girder bridges was conducted with different piers:a cast-in-place reinforced concrete pier,a grouting sleeve-fabricated pier,and a grouting sleeve-prestressed tendon composite fabricated pier.Furthermore,the seismic performance of the composite fabricated pier was investigated.The results show that the OpenSees fiber element model can successfully simulate the hysteresis behavior and failure mode of the grouted sleeve-fabricated pier.Under traditional non-near-fault ground motions,the pier top displacements of the grouting sleeve-fabricated pier and the composite fabricated pier were less than those of the cast-in-place reinforced concrete pier.The composite fabricated pier had a good self-centering capability.In addition,the plastic hinge zones of the grouting sleeve-fabricated pier and the composite fabricated pier shifted to the joint seam and upper edge of the grouting sleeve,respectively.The composite fabricated pier with optimal design parameters has good seismic performance and can be applied in high-intensity seismic areas;however,the influence of pile-soil interaction on its seismic performance should not be ignored.
基金financial support from the Key Program of National Natural Science Foundation of China(Grant No.52130905).
文摘In the new tunnel under close distance through the existing tunnel risk source,the grouting scheme developed to compensate for stratum losses is still based on empirical methods,relying on the overburden thickness of existing tunnels.This can potentially lead to an excessively high or low probability of uplift of existing tunnels.Proposing a coupled deformation analysis method between the grouting construction and adjacent existing tunnels is of great theoretical significance for developing grouting schemes.In order to reasonably limit the design parameters of grouting construction,based on the theory of fluid–solid coupling elastic pore-column expansion and the theory of random media,the calculation method of stratum displacement which simultaneously considers the coexistence of grout compaction expansion and permeability diffusion mode is derived,and the accuracy of the calculation method is verified by engineering examples.The accuracy of this calculation method was verified through engineering examples.Combined with the deformation coordination condition,the existing tunnel is regarded as an elastic Euler-Bernoulli continuous beam,and the finite element coupling balance equation of the interaction between the existing tunnel and the surrounding soil is obtained.Based on this,a coupling calculation model of the grouting construction and the deformation response of the adjacent existing tunnel is established.Combined with three times of grouting construction examples in the shield tunneling project of Beijing Metro Line 12 under the existing airport line,the reliability of the coupling calculation model to determine the grouting construction parameters is verified.The calculation parameters in the coupling calculation model have clear physical meanings,which can provide a theoretical basis for the grouting design of similar risk source projects.
