Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side en...Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side entry retaining are obtained via physical simulation and theoretical analysis,in which the scope of disturbed strata is enlarged from main roof to fracture zone.The experiment reveals that as a working face advances,roof strata sequentially collapse from bottom to top and produce multiple disturbances to gob-side entry retaining.Key strata among the overlying strata control each collapse.Main roof subsidence is divided into three stages:flexure subsidence prior to rupture,rotational subsidence during rupture and compressive subsidence after rupture.The amounts of deformation evident in each of the three stages are 15%,55%and 30%,respectively.After the master stratum collapses,main roof subsidence approaches its maximum value.The final span of the key stratum determines the moment and cycling of gob-side entry retaining disturbances.Main roof subsidence influences the load on the filling wall.The sequential roof collapse of overlying strata results in fluctuations in the gob-side entry retaining deformation.Calculation formulae for the final span of the key stratum and the filling wall load are obtained via theoretical analysis.A control method for the stability of the gob-side entry retaining’s surrounding rock is proposed,which includes 3 measures:a“dual-layer”proactive anchorage support,roadside filling with dynamic strength matching and auxiliary support during disturbance.Finally,the gob-side entry retaining of the Xiaoqing mine E1403 working face is presented as an engineering case capable of verifying the validity of the research conclusions.展开更多
In this letter,we first put forward a new basic problem to the famous vector perturbation(VP) precoding that whether the extended constellation of VP could transmit more information bits.Then,we propose an opportunist...In this letter,we first put forward a new basic problem to the famous vector perturbation(VP) precoding that whether the extended constellation of VP could transmit more information bits.Then,we propose an opportunistic vector perturbation(OVP) precoding with superposition signalling scheme,which is aimed at getting the performance of VP closer to capacity limit.The main idea is using subsequent recoverable data symbol vector to perturb currently transmitting data symbol vector opportunistically.Analysis and simulation results show that the proposed OVP can transmit more valid information bits than conventional VP at the same transmit power,modulation order and number of antennas.展开更多
基金Project(51404251)supported by the National Natural Science Foundation of ChinaProject(BK20140198)supported by the Natural Science Foundation of Jiangsu Province,China+1 种基金Project(PPZY2015A046)supported by the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side entry retaining are obtained via physical simulation and theoretical analysis,in which the scope of disturbed strata is enlarged from main roof to fracture zone.The experiment reveals that as a working face advances,roof strata sequentially collapse from bottom to top and produce multiple disturbances to gob-side entry retaining.Key strata among the overlying strata control each collapse.Main roof subsidence is divided into three stages:flexure subsidence prior to rupture,rotational subsidence during rupture and compressive subsidence after rupture.The amounts of deformation evident in each of the three stages are 15%,55%and 30%,respectively.After the master stratum collapses,main roof subsidence approaches its maximum value.The final span of the key stratum determines the moment and cycling of gob-side entry retaining disturbances.Main roof subsidence influences the load on the filling wall.The sequential roof collapse of overlying strata results in fluctuations in the gob-side entry retaining deformation.Calculation formulae for the final span of the key stratum and the filling wall load are obtained via theoretical analysis.A control method for the stability of the gob-side entry retaining’s surrounding rock is proposed,which includes 3 measures:a“dual-layer”proactive anchorage support,roadside filling with dynamic strength matching and auxiliary support during disturbance.Finally,the gob-side entry retaining of the Xiaoqing mine E1403 working face is presented as an engineering case capable of verifying the validity of the research conclusions.
基金supported in part by Key Project of National Natural Science Foundation of China(61231008)National Natural Science Foundation of China (61301168,61271176)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China (2013JQ8001)Fundamental Research Funds for the Central Universities and the 111 Project(B08038)
文摘In this letter,we first put forward a new basic problem to the famous vector perturbation(VP) precoding that whether the extended constellation of VP could transmit more information bits.Then,we propose an opportunistic vector perturbation(OVP) precoding with superposition signalling scheme,which is aimed at getting the performance of VP closer to capacity limit.The main idea is using subsequent recoverable data symbol vector to perturb currently transmitting data symbol vector opportunistically.Analysis and simulation results show that the proposed OVP can transmit more valid information bits than conventional VP at the same transmit power,modulation order and number of antennas.
