We present a series of experimental tests on chemical grouting into a fracture with flowing and static water,using a transparent fracture grouting experimental device.Variations of seepage pressure and grout propagati...We present a series of experimental tests on chemical grouting into a fracture with flowing and static water,using a transparent fracture grouting experimental device.Variations of seepage pressure and grout propagation were compared in our investigation.The results show that flowing water results in drops of seepage pressure,development of penetration radii in the upstream side and drops of propagation area during the same period,compared with grouting in static water.The propagation area in static water is always round before grouts reach the joint boundaries.However,the propagation shape changes from round to an elliptic shape for grouting into a fracture with flowing water.A theoretical model for the grout penetration radius in a fracture considering flowing velocity was developed and validated by our experimental results.These results are helpful in improving understanding of fracture grouting mechanism and in guiding engineering practices.展开更多
Experimental tests show that static pre-loading has a significant effect on the dynamic strength of concrete.Based on meso-scale particle element model,numerical simulations of dynamic bending tests with pre-loading a...Experimental tests show that static pre-loading has a significant effect on the dynamic strength of concrete.Based on meso-scale particle element model,numerical simulations of dynamic bending tests with pre-loading are performed.Complete stress–strain relationships are then obtained.Significant increase in dynamic strength is found when the pre-loadings are imposed within the elastic limit of concrete.However,when the imposition of pre-loadings reaches the plastic or softening range,dynamic strengths may gradually decrease along with the increase in pre-loadings.The distribution of energy components and the failure modes are discussed to explain the mechanisms of the phenomena.展开更多
基金Financial support for this work,provided by the National Natural Science Foundation of China(Nos.40772192 and 41072237)the State Key Laboratort of Geomechanics and Deep Underground Engineering(No.SKLGDUEK0903)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20100095110015)
文摘We present a series of experimental tests on chemical grouting into a fracture with flowing and static water,using a transparent fracture grouting experimental device.Variations of seepage pressure and grout propagation were compared in our investigation.The results show that flowing water results in drops of seepage pressure,development of penetration radii in the upstream side and drops of propagation area during the same period,compared with grouting in static water.The propagation area in static water is always round before grouts reach the joint boundaries.However,the propagation shape changes from round to an elliptic shape for grouting into a fracture with flowing water.A theoretical model for the grout penetration radius in a fracture considering flowing velocity was developed and validated by our experimental results.These results are helpful in improving understanding of fracture grouting mechanism and in guiding engineering practices.
基金supported by the National Natural Science Foundation of China(Grant Nos.51239006,91215301 and 51479098)
文摘Experimental tests show that static pre-loading has a significant effect on the dynamic strength of concrete.Based on meso-scale particle element model,numerical simulations of dynamic bending tests with pre-loading are performed.Complete stress–strain relationships are then obtained.Significant increase in dynamic strength is found when the pre-loadings are imposed within the elastic limit of concrete.However,when the imposition of pre-loadings reaches the plastic or softening range,dynamic strengths may gradually decrease along with the increase in pre-loadings.The distribution of energy components and the failure modes are discussed to explain the mechanisms of the phenomena.
