Advanced Materials Research Vols. 962-965

Abstract: The article analysis and summary how to control the final pressure value of site operation by taking project in Changchun as an example when the cohesive soil layer use static prestressed concrete pipe pile foundation, putting forward the methods and suggestions of controlling final pressure value.

Abstract: The coal can produce electromagnetic radiation when it is in the loading process. The electromagnetic radiation characteristics testing to the sample in the process of uniaxial compression failure in the lab shows that loading stress and the strength of electromagnetic radiation, the number of electromagnetic radiation pulse, the number of acoustic emission pulse are positively correlated relationship when it is in the loading process. They usually have a good corresponding relationship with each other, but are not completely synchronization. They test the corresponding relationship between the electromagnetic radiation intensity of coal and main parameters gas emission initial speed of traditional prediction of coal and gas outburst borehole and amount of drilling cuttings. The results show that the electromagnetic radiation intensity and gas emission initial speed of borehole and amount of drilling cuttings have a positive correlation, and the linear positive correlation equation is obtained. Thus it can be seen, electromagnetic radiation characteristics can be used for predicting the outburst of coal and gas.

Abstract: Cellular Automata is a discrete dynamic model based on space-time, and is one of the effective methods to study complex systems. The CA, a new method applied to coal mining subsidence dynamic evolution model, provide a new idea for the prediction research of mining subsidence. Definition and basic theory of CA were introduced briefly. According to the particularity of the research in the field of mining subsidence, the definition of CA is extended. The model of dynamic evolution of mining subsidence is built on the CA. Then modeling method and the structure of model are elaborated, and the advantages of the CA are applied to coal mining subsidence prediction model is analyzed.

Abstract: Based on overburden of S2S9 working face fully-mechanized mining of certain coal mine, this paper uses the finite element ADINA software to analyze the vertical stress and shear stress of overburden under the condition of coal mining, especially the vertical stress decreasing and increasing zones, concentrated stress change and to discuss the distribution scope, peak value and spatial relation with the working face of Tre-suptorping stress. The study on the mine safe and efficient mining of other face has certain significance.

Abstract: In order to obtain overburden and surface deformation law, this paper takes S2S9 working face fully-mechanized mining of certain coal mine for example, uses the finite element ADINA software, and it establishes two-dimensional numerical model, analyzes overburden and surface deformation caused by the working face mining. The study shows the amount of each point movement in the top of the mined-out area gradually decreases from the bottom to up, and the range of surface movement is also increasing with advancement of the coal excavation. After the completion of the working face, it forms a subsidence curve which is symmetry for the maximum vertical point and an antisymmetric horizontal deformation curve. The zero point of horizontal movement is located above the center of mining sector, and the maximum tilt is 2.044mm·m.

Abstract: Coal mine roadway deformation have a significant impact on coal mine production. Based on the Arduino microcontroller system and ultrasonic distance sensor, through temperature compensation and system fixes, designed a roadway deformation monitoring system which is high accuracy, low price and simple operation. Monitoring results through the LCD display, and SD card for data storage, the system achieved real-time monitoring of roadway deformation. The system was actually tested in coal mine, and achieved good monitoring results.

Abstract: The stress of slope is in dynamic changes from open-pit to underground of the mining excavation . In this article, based on the relationship of space corresponding through the two mining methods, and two types of mining influence dominated overprint and containing characteristics, it can find out its regularity according to the numerical simulation, and also can reveal the induced with mutual interference between two excavation system mechanism, deformation of foundation and its numerical size out of dangerous area from the mining effect of interaction and mutual superposition characteristics; On this basis, it also analyzes its influence on the stability of the slope characteristics and deformation law, and puts forward to the control methods which provide the decisions basis for the mining safety production.

Abstract: For less study on coal rock floor fracture distribution of upper protective layer mining process, by numerical simulation and similarity simulation combined to get failure characteristics of distribution on the floor with the protective layer mining ,divided into deformation-failure zone and plastic deformation zone of seam floor, with the same time divided each zone height of "upper three zone". Regional outburst prevention measures as the most effective, a mine protective layer mining practice, investigated the protective effect of the protective layer on the protected layer after mining coal seam gas pressure, gas content, permeability coefficient changes, Because of the protective layer at the plastic deformation zone of seam floor, the gas release have a good effect .By numerical simulation and similarity simulation test combined, get protective layer mining floor failure distribution. Keywords: upper protevtive layer;Similar simulation;numerical simulation; failure characteristics ;protection effect.

Abstract: In order to further improve the recovery ratio in strip mining, this paper makes use of the law of insufficiency and sufficiency in strata movement and buildings’ additional stress release features, puts forward twice strip mining technology. The paper introduces the method and feasibility of twice strip mining. By analyzing karst cave collapse mechanism, the paper points out vertical cracks and horizontal layer separations are the direct causes of karst caves collapses and small strength mining each time can reduce karst cave collapse. The new technology has been applied in Pinghu Mine. It has totally extracted recoverable coal reserves under village buildings, effectively controlled strata deformation, and successfully avoided karst cave collapse within Yangkeng village.

Abstract: As the shape of the bearing push-extend reamed can influence failure modes of the soil around the pile and below the disk, this paper, through experimental research that different shapes of the bearing push-extend reamed have influence on the capacity of the single push-extend Multi-under-reamed pile under the same loads, provides a reliable basis for further ascertaining the capacity of the push-extend Multi-under-reamed pile with the theory of sliding line.