According to the tensile failure of rock bolt in weakly cemented soft rock, this paper presents a new segmented anchoring style in order to weaken the cumulative effect of anchoring force associated with the large def...According to the tensile failure of rock bolt in weakly cemented soft rock, this paper presents a new segmented anchoring style in order to weaken the cumulative effect of anchoring force associated with the large deformation. Firstly, a segmented mechanical model was established in which free and anchoring section of rock bolt were respectively arranged in different deformation zones. Then, stress and displacement in elastic non-anchoring zone, elastic anchoring zone, elastic sticking zone, softening sticking zone and broken zone were derived respectively based on neural theory and tri-linear strain softening constitutive model of soft rock. Results show that the anchoring effect can be characterized by a supporting parameter b. With its increase, the peak value of tangential stress gradually moves to the roadway wall, and the radial stress significantly increases, which means the decrease of equivalent plastic zone and improvement of confining effect provided by anchorage body. When b increases to 0.72, the equivalent plastic zone disappears, and stresses tend to be the elastic solutions. In addition, the anchoring effect on the displacement of surrounding rock can be quantified by a normalization factor δ.展开更多
Based on a shallow roadway with weakly cemented soft strata in western China, this paper studies the range and degree of plastic zones in soft strata roadways with weak cementation. Geological radars were used to moni...Based on a shallow roadway with weakly cemented soft strata in western China, this paper studies the range and degree of plastic zones in soft strata roadways with weak cementation. Geological radars were used to monitor the loose range and level of surrounding rocks. A mechanical model of weakly cemented roadway was established, including granular material based on the measured results. The model was then used to determine the plastic zone radium. The predicted results agree well with measured results which provide valuable theoretical references for the analysis of surrounding rock stability and support reinforcing design of weakly cemented roadways. Finally, a combined supporting scheme of whole section bolting and grouting was proposed based on the original supporting scheme. It is proved that this support plan can effectively control the deformation and plastic zone expansion of the roadway surrounding rock and thus ensure the long-term stable and safe mining.展开更多
From observing cores of 18 wells,identifying 175 ordinary thin sections and 61 thin casting sections,energy spectrum analyses of 37 samples,homogenization temperature measurement of fluid inclusions of 11 samples,we d...From observing cores of 18 wells,identifying 175 ordinary thin sections and 61 thin casting sections,energy spectrum analyses of 37 samples,homogenization temperature measurement of fluid inclusions of 11 samples,we determine the types of diagenesis and pores of the Fuyu oil reservoir in the north Qijia region.We classified the pores and measured their plane porosity using CIA 2000,the software of rock image analysis,calculated the effect of different kinds of diagenesis on porosity,studied the controlling actions of diagenesis to pore evolution quantitatively,combined with burial history,thermal history and their diagenetic environments.Our results show that mechanical compaction and carbonate cementation are the major destructive diagenesed,developed during early diagenesis stages.The reduction in porosity by mechanical compaction and carbonate cementation are about 25% and 8%,while the destructive intensity of siliceous cementation and clay mineral cementation is relatively much smaller,i.e.,the reduction of porosity is about 2% and 0.2% Dissolution is constructive diagenesis,the increment of porosity is about 6%.There are four diagenesis evolution stages,during which the porosity reduced from 30%～38% to 2%～20%.Mechanical compaction and early cementation are the main diageneses in the early diagenesis stages,when porosity was reduced to 2%～10%.Dissolution is the main diagenesis of an A I substage of the middle diagenesis stage,when porosity increased 1%～8%.The dissolution of the A Ⅱ substage of the middle diagenesis stage affected by late cementation,raised porosity 1%～5%.The porosity varied slightly during the middle stage B.展开更多
基金Financial support for this work was provided by the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents of China(No.2015RCJJ042)the National Natural Science Foundation of China(Nos.41472280,51274133)+1 种基金the Promotive Research Fund for Excellent Young and Middle-aged Scientisits of Shandong Province of China(No.BS2015SF005)the Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation(No.CDPM2013KF05)
文摘According to the tensile failure of rock bolt in weakly cemented soft rock, this paper presents a new segmented anchoring style in order to weaken the cumulative effect of anchoring force associated with the large deformation. Firstly, a segmented mechanical model was established in which free and anchoring section of rock bolt were respectively arranged in different deformation zones. Then, stress and displacement in elastic non-anchoring zone, elastic anchoring zone, elastic sticking zone, softening sticking zone and broken zone were derived respectively based on neural theory and tri-linear strain softening constitutive model of soft rock. Results show that the anchoring effect can be characterized by a supporting parameter b. With its increase, the peak value of tangential stress gradually moves to the roadway wall, and the radial stress significantly increases, which means the decrease of equivalent plastic zone and improvement of confining effect provided by anchorage body. When b increases to 0.72, the equivalent plastic zone disappears, and stresses tend to be the elastic solutions. In addition, the anchoring effect on the displacement of surrounding rock can be quantified by a normalization factor δ.
基金provided by the National 973 Programs(No.2014CB046905)the National Natural Science Foundation of China(Nos.51274191 and 51404245)+1 种基金the Doctoral Fund of Ministry of Education(No.20130095110018)China Postdoctoral Science Foundation(No.2014M551699)
文摘Based on a shallow roadway with weakly cemented soft strata in western China, this paper studies the range and degree of plastic zones in soft strata roadways with weak cementation. Geological radars were used to monitor the loose range and level of surrounding rocks. A mechanical model of weakly cemented roadway was established, including granular material based on the measured results. The model was then used to determine the plastic zone radium. The predicted results agree well with measured results which provide valuable theoretical references for the analysis of surrounding rock stability and support reinforcing design of weakly cemented roadways. Finally, a combined supporting scheme of whole section bolting and grouting was proposed based on the original supporting scheme. It is proved that this support plan can effectively control the deformation and plastic zone expansion of the roadway surrounding rock and thus ensure the long-term stable and safe mining.
基金the National Basic Research Program of China (No.2009 CB219306)the Important National Science & Technology Specific Projects (No.2009GYXQ14)
文摘From observing cores of 18 wells,identifying 175 ordinary thin sections and 61 thin casting sections,energy spectrum analyses of 37 samples,homogenization temperature measurement of fluid inclusions of 11 samples,we determine the types of diagenesis and pores of the Fuyu oil reservoir in the north Qijia region.We classified the pores and measured their plane porosity using CIA 2000,the software of rock image analysis,calculated the effect of different kinds of diagenesis on porosity,studied the controlling actions of diagenesis to pore evolution quantitatively,combined with burial history,thermal history and their diagenetic environments.Our results show that mechanical compaction and carbonate cementation are the major destructive diagenesed,developed during early diagenesis stages.The reduction in porosity by mechanical compaction and carbonate cementation are about 25% and 8%,while the destructive intensity of siliceous cementation and clay mineral cementation is relatively much smaller,i.e.,the reduction of porosity is about 2% and 0.2% Dissolution is constructive diagenesis,the increment of porosity is about 6%.There are four diagenesis evolution stages,during which the porosity reduced from 30%～38% to 2%～20%.Mechanical compaction and early cementation are the main diageneses in the early diagenesis stages,when porosity was reduced to 2%～10%.Dissolution is the main diagenesis of an A I substage of the middle diagenesis stage,when porosity increased 1%～8%.The dissolution of the A Ⅱ substage of the middle diagenesis stage affected by late cementation,raised porosity 1%～5%.The porosity varied slightly during the middle stage B.
