Deep coal mining rock support structures using rock bolts face complex geological conditions such as high ground temperatures and groundwater.Rock mass deformation and failure caused by bolt failure frequently occur,m...Deep coal mining rock support structures using rock bolts face complex geological conditions such as high ground temperatures and groundwater.Rock mass deformation and failure caused by bolt failure frequently occur,making it crucial to enhance the anchoring performance of rock bolts.First,the stress state of the anchor rod under axial loading across five stages of any anchored segment is analyzed.The shear stress patterns at the anchoring interface during different stages are elucidated.A refined mechanical model of the anchoring interface incorporating surface rib parameters is established.A failure criterion for the anchoring interface under the influence of ground temperature or groundwater is derived and validated.Second,the influence of anchor rib parameters on anchoring force is abalyzed,and in-situ shear tests are conducted.Results indicate that increasing the rib angle and optimizing rib spacing can enhance anchoring force.To minimize the shear component of axial force at the anchor interface,the rib angle of the anchor bolt should not be less than 70°.When the anchor grout possesses high inherent strength,the spacing between ribs on the anchor bolt surface may be increased(to 24 mm or greater).Finally,methods for enhancing the anchoring performance of bolts in deep complex strata are proposed,providing technical references for the safe and efficient support of tunnel rock masses in similar geological conditions.展开更多
In order to study the failure process of an anchorage structure and the evolution law of the body＇s defor- mation field, anchor push-out tests were carried out based on digital speckle correlation methods （DSCM）. T...In order to study the failure process of an anchorage structure and the evolution law of the body＇s defor- mation field, anchor push-out tests were carried out based on digital speckle correlation methods （DSCM）. The stress distribution of the anchorage interface was investigated using the particle flow numerical simulation method. The results indicate that there are three stages in the deformation and fail- ure process of an anchorage structure： elastic bonding stage, a de-bonding stage and a failure stage. The stress distribution in the interface controls the stability of the structure. In the elastic bonding stage, the shear stress peak point of the interface is close to the loading end, and the displacement field gradually develops into a ＂V＂ shape, in the de-bonding stage, there is a shear stress plateau in the center of the anchorage section, and shear strain localization begins to form in the deformation field. In the failure stage, the bonding of the interface fails rapidly and the shear stress peak point moves to the anchorage free end. The anchorage structure moves integrally along the macro-cracl~ The de-bonding stage is a research focus in the deformation and failure process of an anchorage structure, and plays an important guiding role in roadway support design and prediction of the stability of the surrounding rock.展开更多
基金The Natural Science Research Project of Anhui Educational Committee(No.2022AH050814)Open Fund of State Key Laboratory of Nuclear Resources and Environment(East China Universityof Technology)(No.2022NRE07)+1 种基金the National Natural Science Foundation of China(No.51964002,52174104)Open Fund of Engineering Research Center of Underground Mine Construction of Ministry of Education(No.JYBGCZX2022105).
文摘Deep coal mining rock support structures using rock bolts face complex geological conditions such as high ground temperatures and groundwater.Rock mass deformation and failure caused by bolt failure frequently occur,making it crucial to enhance the anchoring performance of rock bolts.First,the stress state of the anchor rod under axial loading across five stages of any anchored segment is analyzed.The shear stress patterns at the anchoring interface during different stages are elucidated.A refined mechanical model of the anchoring interface incorporating surface rib parameters is established.A failure criterion for the anchoring interface under the influence of ground temperature or groundwater is derived and validated.Second,the influence of anchor rib parameters on anchoring force is abalyzed,and in-situ shear tests are conducted.Results indicate that increasing the rib angle and optimizing rib spacing can enhance anchoring force.To minimize the shear component of axial force at the anchor interface,the rib angle of the anchor bolt should not be less than 70°.When the anchor grout possesses high inherent strength,the spacing between ribs on the anchor bolt surface may be increased(to 24 mm or greater).Finally,methods for enhancing the anchoring performance of bolts in deep complex strata are proposed,providing technical references for the safe and efficient support of tunnel rock masses in similar geological conditions.
基金financially supported by the National Key Basic Research Program of China (No.2010CB226805)the National Natural Science Foundation of China (Nos.51474136 and 51474013)+1 种基金the Opening Project Fund of State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology (No.MDPC2013KF06)the Research Award Fund for the Excellent Youth of Shandong University of Science and Technology (No.2011KYJQ106)
文摘In order to study the failure process of an anchorage structure and the evolution law of the body＇s defor- mation field, anchor push-out tests were carried out based on digital speckle correlation methods （DSCM）. The stress distribution of the anchorage interface was investigated using the particle flow numerical simulation method. The results indicate that there are three stages in the deformation and fail- ure process of an anchorage structure： elastic bonding stage, a de-bonding stage and a failure stage. The stress distribution in the interface controls the stability of the structure. In the elastic bonding stage, the shear stress peak point of the interface is close to the loading end, and the displacement field gradually develops into a ＂V＂ shape, in the de-bonding stage, there is a shear stress plateau in the center of the anchorage section, and shear strain localization begins to form in the deformation field. In the failure stage, the bonding of the interface fails rapidly and the shear stress peak point moves to the anchorage free end. The anchorage structure moves integrally along the macro-cracl~ The de-bonding stage is a research focus in the deformation and failure process of an anchorage structure, and plays an important guiding role in roadway support design and prediction of the stability of the surrounding rock.
