We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle.We concentrate on structures built of osteomorphic blocks-the blocks ...We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle.We concentrate on structures built of osteomorphic blocks-the blocks possessing specially engineered contact surfaces allowing assembling various 2D and 3D structures.These structures are easy to build and can be made demountable.They are flexible,resistant to macroscopic fractures and tolerant to missing blocks.The blocks are kept in place without keys or connectors that are the weakest elements of the conventional interlocking structures.The overall structural integrity of these structures depends on the force imposed by peripheral constraint.The peripheral constraint can be provided in various ways:by an external flame or features of site topography,intemal prestressed cables/tendons,or self-weight and is a necessary auxiliary element of the structure.The constraining force also determines the degree of delamination developing between the blocks due to bending and thus controls the overall flexibility of the structure thus becoming a new design parameter.展开更多
Deep geothermal from the hot crystalline basement has remained an unsolved frontier for the geothermal industry for the past 30 years. This poses the challenge for developing a new unconventional geomechanics approach...Deep geothermal from the hot crystalline basement has remained an unsolved frontier for the geothermal industry for the past 30 years. This poses the challenge for developing a new unconventional geomechanics approach to stimulate such reservoirs. While a number of new unconventional brittle techniques are still available to improve stimulation on short time scales, the astonishing richness of failure modes of longer time scales in hot rocks has so far been overlooked. These failure modes represent a series of microscopic processes： brittle microfracturing prevails at low temperatures and fairly high deviatoric stresses, while upon increasing temperature and decreasing applied stress or longer time scales, the failure modes switch to transgranular and intergranular creep fractures. Accordingly, fluids play an active role and create their own pathways through facilitating shear localization by a process of time-dependent dissolution and precipitation creep, rather than being a passive constituent by simply following brittle fractures that are generated inside a shear zone caused by other localization mechanisms. We lay out a new theoretical approach for the design of new strategies to utilize, enhance and maintain the natural permeability in the deeper and hotter domain of geothermal reservoirs. The advantage of the approach is that, rather than engineering an entirely new EGS reservoir, we acknowledge a suite of creep-assisted geological processes that are driven by the current tectonic stress field. Such processes are particularly supported by higher temperatures potentially allowing in the future to target commercially viable combinations of temperatures and flow rates.展开更多
基金This research was supported through the ARC Discovery Grant DP120102434AVD and EP also acknowledge support through the ARC Discovery grant DP0988449.
文摘We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle.We concentrate on structures built of osteomorphic blocks-the blocks possessing specially engineered contact surfaces allowing assembling various 2D and 3D structures.These structures are easy to build and can be made demountable.They are flexible,resistant to macroscopic fractures and tolerant to missing blocks.The blocks are kept in place without keys or connectors that are the weakest elements of the conventional interlocking structures.The overall structural integrity of these structures depends on the force imposed by peripheral constraint.The peripheral constraint can be provided in various ways:by an external flame or features of site topography,intemal prestressed cables/tendons,or self-weight and is a necessary auxiliary element of the structure.The constraining force also determines the degree of delamination developing between the blocks due to bending and thus controls the overall flexibility of the structure thus becoming a new design parameter.
基金support from the China University of Geosciences (CUG) for visiting the conference in Wuhan in 2012
文摘Deep geothermal from the hot crystalline basement has remained an unsolved frontier for the geothermal industry for the past 30 years. This poses the challenge for developing a new unconventional geomechanics approach to stimulate such reservoirs. While a number of new unconventional brittle techniques are still available to improve stimulation on short time scales, the astonishing richness of failure modes of longer time scales in hot rocks has so far been overlooked. These failure modes represent a series of microscopic processes： brittle microfracturing prevails at low temperatures and fairly high deviatoric stresses, while upon increasing temperature and decreasing applied stress or longer time scales, the failure modes switch to transgranular and intergranular creep fractures. Accordingly, fluids play an active role and create their own pathways through facilitating shear localization by a process of time-dependent dissolution and precipitation creep, rather than being a passive constituent by simply following brittle fractures that are generated inside a shear zone caused by other localization mechanisms. We lay out a new theoretical approach for the design of new strategies to utilize, enhance and maintain the natural permeability in the deeper and hotter domain of geothermal reservoirs. The advantage of the approach is that, rather than engineering an entirely new EGS reservoir, we acknowledge a suite of creep-assisted geological processes that are driven by the current tectonic stress field. Such processes are particularly supported by higher temperatures potentially allowing in the future to target commercially viable combinations of temperatures and flow rates.
