Advanced Materials Research Vols. 524-527

Abstract: The numerical simulation of migration rule about dust flow field in typical long forcing and short exhausting mixed ventilation dust removal system of half-coal rock fully-mechanized excavation face was carried out, and local ventilation system was improved based on the simulation results. The relative position relationship of ventilation facilities and the matching relationship of forcing and exhausting air volume in half-coal roadway were made sure, thus, the new complete sets of ventilation wet dedusting system with the type of KTCS-500L had been developed. According to the application in Nantun coal mine of Yanzhou mining group, the system proved to be very effective.

Abstract: Horizontal well is the main technology to develop bottom-water sandstone reservoirs. Water coning has a significant influence on development effect, and shut-in coning control is one of coning suppression methods. Based on the geological model of a given oilfield, this paper has made an evaluation of water coning control by numerical simulation. It can be concluded that the method of shut-in coning control is effective for low water cut wells. When shutting in, the lower the water cut is, the greater decline extent of water cut can be obtained and the higher cumulative oil production can be achieved after well reopening. The longer the close time is, the better water coning control effect can be acquired, however it will affect oil production undoubtly. When horizontal well enters into high water cut stage, shut-in coning control not only has almost no effect, but also has a negative impact on the normal oil production.

Abstract: By using triaxial stress thermal-hydro-mechanical coal containing gas permeameter，mechanical and gas seepage characteristics is researched under different confining pressure、different initial axial stress and different unloading speed of confining pressure，the results shows that the increasing of unloading speed of confining pressure and the initial axial stress will shorten the time of the time of axial stress platform，From the aspect of gas permeation，the increasing of unloading speed of confining pressure and intial axial stress will accelerate the increasing of permeability，therefore， reasonable arrangement of roadway and method which can reduce the supporting stress should be proceed to preventing the outburst accident.

Abstract: Spontaneous combustion in coal goaf area is one of major disasters in coal mines. Detection technology based on signature Gas and Temperature is the primary means of spontaneous combustion forecasting of coal goaf area. A real-time remote fire detection system is proposed based on tunable diode laser absorption spectroscopy technology and FBG temperature sensing technology, to achieve valid detect of gas concentration and temperature. The System include fiber mathen concentration sensor and fiber temperature sensor based FBG. The system achieved remote on-line monitoring of gas concentration and temperature in mine goaf, meet the fire forecast need for Coal goaf area. There are obvious advantages Compared with the existing beam tube monitoring system in coal mine.

Abstract: Contraposing a lead-zinc ore in yunnan province, Adopting FLAC3D which is a three-dimensional finite differential method to analyse the slope stability induced by goaf, The results indicated:the movement of surrounding rock had been being more intense, meanwhile the slope was instability,It might cause collapse and land slide of slope rock if no using filling method to treat timely.The sizeof plastic zone in slope rock reduced greatly after filling the goaf, that greatly improved slope stability. Results of simulation were in line with practical producing, validating that FLAC3D was an effective way of slope stability analysis induced by goaf.

Abstract: With ShapeMetriX3D rock non-contact measuring technology, structural planes’ distribution of MiaoGou iron mine slope is got. Then, the Mont-Carlo method is used to create equivalent fracture network, with that scale effects and anisotropic properties of rock mass are studied by RFPA2D, considering different scales and directions in statistical window. The results show that both deformation modulus and the strength of the rock mass’s REV are 2.5 m. Furthermore, the strength ratio of filler to rock (K) and the strength of the rock mass fit the logarithmic relationship in rough, while the elastic modulus ratio of filler to rock (M) and the strength of the rock mass fit the linear relationship in rough. The strength of no joints rock mass is much stronger than three times of the strength of jointed rock mass, but the rock mass elastic modulus of no joints is less than 1.6 times of the elastic modulus of jointed rock mass. The research results are directive and have reference value for the study of anisotropy mechanical parameters of rock mass engineering.

Abstract: This paper aimed at fire control in thick seam large-scale top-carving region. On the basis of coal and oxygen compounding theory, theoretical analysis, numerical simulation and experiment are combined, and a coal spontaneous combustion process model is built according to fluid mechanics and control theory. By studying and testing on top-carving coal spontaneous combustion process, conclusion is drawn that spontaneous combustion area is the largest in partly-closed region, followed by unclosed region. A totally closed baffle leads to the smallest spontaneous combustion area and the smallest possibility of fire. With local materials in a certain condition, new, cheap backfilling materials are developed. Thus provide theoretical basis for study on the forecasting and prevention of thick seam large-scale top-carving coal spontaneous combustion.

Abstract: The phenomenon of great difference of mishap rate for roof collapse in the stope of a mine between day and night has been found in accordance with our observation in operational jobsite and the informations recorded over past 30 years,witch is regarded as a phenomenon of gravitational effect and is in the know by the inference of Newton’s Gravitational Principle that in general no one can explain it clearly by means of “mine pressure”,neverthless the major reason is that the direction of pressure on the stope roof between day and night is oppsite to the direction of the lunar gravitation (normal component force),and after it superposed onto the terrestmal gravity,their composite forces (PC) are different so that the pressure on roof is also various,greater in the night time and lighter in the daytime.this is why the roof collapse occurred in the nighttime is greater than that in the daytime.

Abstract: According to the questions of long eliminating coal and gas outburst period, large projects and slow driving came from the regional measurement of drilling hole ,the paper select 2371 (1) rail transport roadway as experiment for using along seam long drilling as a regional measurement to eliminate coal and gas outburst. Since the regional measurement of along seam long drilling had been carried out, the remaining gas content decreased more than 60％, max Smax was 5.4kg/m, max qmax was 2.01/min.Both Smax and qmax were not beyond the standard. Gas concentrations were not overrun. Gas emission decreased in the roadway afterward. The regional measurement eliminated the risk of coal and gas outburst in effect. Heading face promoted 423m forward safely. The max January footage could reach 120m.Achieve driving of heading face safely and fast.

Abstract: The prediction of residual subsidence is the fundament of stability evaluation of buildings foundation in the abandoned mine goaf, so how to get the residual subsidence with high precision is significant to reclaim the goaf for buildings. In this paper, a novel prediction model named wavelet support vector machines (WT-SVM) is proposed to forecast residual subsidence. Aiming at the stochastic fluctuation of the subsidence series, the measured data of residual subsidence were separated into components, namely, trend, oscillating sequence and stochastic signal, via wavelet multi-resolution analysis; then, the prediction model was established based on SVM regression algorithm, respectively, and the sum of the total corresponding prediction values were regarded as the final results of the residual subsidence. The predicting results of WT-SVM, SVM and BP neural network (BP-NN) were compared by a case study. The conclusions are as follows: WT-SVM model is obviously superior to other models in terms of the aspects of prediction precision, step and stability, which indicates the feasibility and effectivity of WT-SVM in predicting residual subsidence of the abandoned mine goaf.