Advanced Materials Research Vol. 1020

Abstract: A steel concrete lining is today the common ground massive retaining structure implemented shortly after the excavation of an opening. The constituent elements of the steel concrete lining are layers of shotcrete and steel arch frames. This simple structure has many unique features which set it apart from the conventional reinforced concrete constructions. Without simplification these features doesn’t allow to carry out design and evaluation of steel concrete lining by relevant design and evaluation methods convenient to the conventional reinforced concrete constructions. The main differences are construction process, yielding curve of structure and determination of external load. In the case of a steel concrete lining its external load is product of mutual work of both the ground massive and the lining. The value of load depends on the yielding curves of the lining and the ground massive. The yielding curve of a ground massive is objective and conditioned on strength strain properties of ground massive and primary stress state. The yielding curve of a steel concrete lining relates lining design specification. The process of construction affects the value of load too. The article analyzes the steel concrete lining focusing the influence of lining design parameters on its yielding curve. It looks for a way to control the ground massive behavior and as well as to engage it more in an effort with lining to stabilize subterranean work. The themes of the analysis are: static and deformation parameters of the cross-section of the steel concrete lining with regard to the construction stage and dependency of hardening shotcrete; interaction between of steel concrete lining and ground massive based on yielding curves; assessment of a stress state across the steel concrete lining section in the steel concrete lining constituent elements. The analysis is carried out on mathematical models that combine analytical and numerical methods.

Abstract: This paper presents the results of static tests of non-reinforced and reinforced round timber bolted joints with slotted-in steel plates. In this article, a new approach to the reinforcement of round timber bolted joints is presented. Based on results from tension tests of timber bolted joint samples, reinforcement methods were proposed. From these, modified washers and boost with screws were chosen for further tension testing. Results were compared to unreinforced ones and rate of improvement established.

Abstract: Often due to the pressure gradient change in pressure systems the stationary flow pattern is disturbed initiating respective time-dependent change of hydraumechanical parameters at the cross-section. As a consequence of the pressure gradient change under the influence of varying friction and inertia forces unstable flow of fluid occurs. The study of this phenomenon presents important practical and theoretical interest.

Abstract: Flow of viscous fluid in automation and control hydraulic systems usually is nonstationary. In such conditions research of viscous fluid unstable flow are important first of all for obtaining hydraudynamic parameters of flow and secondly, they will enable to design the system accurately and provide efficient performance of an actuator. Study of nonstationary flow of viscous fluid in cylindrical canals of circular cross-section was carried out when pressure gradiend of stationary moving flow suddenly decreases resulting in slow down of motion of fluid particles. As a result quadrically parabolic pattern of velocities is changed and their rearrangement occurs leading to a change of the flow hydraudynamic parameters. A boundary problem has been defined for the above conditions, preliminary and initial conditions have been determined and respective hydraudynamic parameters of the flow obtained. These parameters enable to reveal energy losses formation mechanism and evaluate their measure.

Abstract: : In the framework of Darcy's law of filtration the investigation results of one class of boundary value problems of the steady-state filtration theory in porous ground base are presented. The plane mixed bounadry value problems on the structural analysis of hydrotechnical con­struction of dam type on filtrating ground base in the form of a layer of finite or infinite thickness are considered. The coefficient of filtration is assumed to be constant, piecewise constant, or changing by the depth of base according to the exponential law, the property of anisotropy of filtration is also taken into account. Axis-symmetric and three-dimentional boundary value problems of the theory of steady-state fluid filtration in a three-dimentional layer of a finite or infinite thickness are discussed. These problems are of the type of Lamb well-known hydrodynamic problems in the theory of steady-state flow of the ideal fluid, when through the circular or rectangular openeing of a rigid screen on the upper bound of the layer the liquid with a definite vertical velocity or with a definite pressure is injected into porous ground base. Here, the fields of velocities and pressures in the layer, as well as flow rates of liquid through the certain sections of the ground base are determined.

Abstract: In statement of the steady-state filtration theory and within the framework of the Darcy`s law plane boundary value problems for the strip-like and wedge-shaped porous ground base are considered when through some system of segments on one face of the base the fluid with a certain vertical velocity or with a certain pressure is injected inside the base. These solutions are reduced to integral equations by means of integral transforms.

Abstract: The statical securing of the building, where is situated on the mining area from the effect of hlubinného dobývání showes number strangeness. In addition to that, on top of The article deals with the issue of rehabilitation of statically substantial failures of churches and its static measures against future effects of undermining.template.

Abstract: Pneumatic transport is one of the most progressive means of mechanization and automation of loose goods transportation. It is used in aluminium, chemical, food, textile, construction and other industries. However, wide use of pneumatic transport is limited by the incomplete information on this subject. In this article provides a description of the design of useful models of the suction intake device пневмотранспортной installation. A useful model was developed with the participation of the author of the staff of the Department of transport and technological machines architectural-building University. The author has developed stages of the suction intake unit and carried out theoretical and experimental research on each step to achieve the most effective operation of the device. In view of the fact that for the main parameters of the suction intake devices of the theory of destroying the fabric of a flooded the air flow is not developed to a sufficient degree, the author has studied the process of propagation and interaction of flooded jet with the surface. The article systematized and presents the results of experimental research on the interaction of flooded jets of air sealing with building materials of different kinds. The author determined the optimal parameters of the process of packed loosening material jets of compressed air at the fence material suction fence device.

Abstract: Based on the practical engineering of the subway station constructed by shallow tunnel, according to the site monitoring data, it is concluded the regular pattern of ground settlement that constructed in CRD method. The longitudinal ground settlement curve affected by the spacing between step 1 and step 3 obviously, there are 5 phases in the curve: the first slow growth phase, the first rapid growth phase, the second slow growth phase, the second rapid growth phase and the stable phase; Although the time of the two rapid growth phases is short, the proportion of the ground settlement in these phases is about 65%-85% of the total ground settlement; it also can be known that basing on the practical monitoring curve, the zone of longitudinal ground settlement is about D on the method of CRD. The lateral ground settlement curve in line with the Gaussian curve, the settlement formula could be calculated according to Peck formula, on the base of these, this paper mainly discusses the relationship between K which means settlement trough width parameter and H/D , the results shows that when H/D is about 1.2, the K is minimum.

Abstract: Based on the engineering background of Beijing unban groundwater levels rebounded, the stress behavior of subway station structure under cases of the groundwater in different water levels from the view of numerical mechanical models is researched in this paper and the working condition of this paper is the actual engineering of the Beijing subway line 10. The results demonstrate different underground water levels could lead to obvious vertical displacements, plastic changes of surrounding soil sand the groundwater level upturn obviously within a certain range make the underground structures deform and float overall. Some conclusions are important references for the further improvements of the design and construction of underground structures, reinforcement of existing substructures.