煤矿论文参考文献及英文文献翻译 第2页
3) In the super critical extraction area above the middle of goaf , caving rupture rock mainly supports vertical pressure stress. It can be compacted by natural pressure as time passing , but since rupture rocks are beyond retrieve , the fissures among rocks will exist forever. It will be compacted again when being suffered additional burden.
4) For the difference of stratum bedded deposit characteristic and each rock formation mechanical property , a large amount of bedded separation fissure will be produced in inflection zone of overburden. Under the influence of underground water and external force , especially vertical burden ,these bed separation fissures may be compactedand closed , which will lead to the subsidence of terrene.Based on the analyses above , we can divide t he“liven up ”of rupture rock mass in abandoned goaf into four types :
1) Under the effect of overburden , the rupture rock in goaf body has long term slow creeping deformation.
2) Under the effect of underground water and air , the rupture rock in goaf will be effloresced , its intensity will be attenuated , and the 优,文-论~文^网
http://www.youerw.com , the rupture rock mass above mining dist rict will lose structure stability again. The external forces mainly include earth quake force , tectonic stress caused by region geological structure , disturbance stress caused by exploding or mining , addition burden on the surface , etc.
According to the research results of similar material physical analogy and finite element method , under the condition of deep goaf , the residual deformation of terrene is mainly a slow subsidence course and its uneven subsidence is limited , so reinforcing buildingsp ability to resist deformation is the main technological measure to guarantee its safety. Under the influence of external force , the unstability of the secondary block beam or key strata of overburden mass in goaf is the main cause for serious terrene subsidence in shallow goaf . So strengt hening the block beam structure above goaf and key strata , raising the carrying capacity of rock mass balanced structure and increasing the steady of the balanced structure are the main methods to strengthen the rupture ground above abandoned goaf .
3 TREATMENT OF RUPTURE ROCK MASS OF SHALLOW LONGWALL GOAF
Under the influence of external force , the destabilizing of the secondary block rock beam or key strata of overburden is the main cause for serious ground subsidence over shallow goaf . So strengthening t he block beam structure or key strata above goaf and raising its bearing ability and stability are the main ways to control rupture foundation rock mass deformation over abandoned workings. These technological methods mainly include the following six types.
1. Back filling and grouting in whole goaf
The whole goaf and mining induced fissure of overburden should be backfilled completely by cement , tailings , flyash , sand or clay , etc. This method can get rid of a hidden peril of ground subsidence.
2.Grouting concrete column for partial support
Drilling large diameter borehole on the construction field forms the grout cement or reinforced concrete column to provide surface building support . The column must pass through rupture rock body and reach the integrate rock body beeow abandoned mine workings.
3.Grouting to strengthen block beam in fracture zone
Grouting to stow the bed separation and crack fissure in fracture zone can st- rength the compound block beam structure into a whole continuous half arch rock beam over goaf . This measure is suitable for strengt hening ground around goaf border with large cave and sub stowed area. It can prevent half arch block beam above the edge of goaf from losing stability.
4.Grouting to strengthen basement in sagging zone
Grouting to strength basement in sagging zone below the building can integrate rupture rock body into a whole to guarantee the buildings p subsidence uniformity.
5.Accumulating pressure processing
This measure is to prepress the ground by accumulating debris or sand , etc , on the area above abandoned goaf , which will make the potential differential settlement of ground take place , then the ground will be compacted and the intensity will be improved. Moreover the subsidence will reduce in practical project later. This method requests that effective load shouldnpt lighter than additional load caused by new buildings.
6.Using high energy rammer to deal with shallow rupture rock body Using high energy rammer to deal with shallow rupture rock body will compact the fissure and bed separation in shallow ground , and increase the load carrying capacity of shallow ground. This method is mainly suitable for the foundation soilt reatment of general civil buildings constructed on the middle area of goaf .
4 DESIGNING MEASURES OF ANTI2DEFORM ATION STRUCTURE
Under the condition of certain mining deep and even load , longwall goaf seldom produces violent subsidence , and the distribution of residual subsidence is continuous and gradually changed.Buildings above abandoned goaf undoubtedly will be influenced by ground residual deformation. The ground deformation , transiting to the upper structure of building through foundation , will make the structure have additional stress and deformation. Adopting the designing measures to improve the coordination relation among the base , foundation and upper structure is the basic method to protect buildings on goaf. By analyzing the coordinate relation between the ground subsidence and buildingps deformation , we conclude t he following three principles during designing buildings with deformation resistant structure .
1.Structure yielding measures
The technological 优,文-论~文^网
http://www.youerw.com deformation gap , reducing unit length of building or designing flexible building with hinge joint steel frames , which can change the positions related to each other.
2.Structure rigidity strengthening measures
These measures are to raise stiffness and in tegrity of building units to increase their resisting ability of terrene deformation , which include strengt hening stiff ness and intensity of each unitps ground , adding structure components , strengthening component , etc. We can design adjustable base , for example , ground composed of thicker plate or concrete base row. We can also use ram to make the upper structure back to its original position if uneven subsidence happens.
3.Joint structure rigidity strengthening and structure yielding measures
For large scale indust rial buildings , the needs of equip mentinstallation and its technological process must be considered , in order that structure rigidity strength- ening and structure yielding measures can be applied entirely. Under this circumstance , we should use some synthesize methods to meet the needs of p- roduction safety.
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