Applied Mechanics and Materials Vols. 368-370

Abstract: In order to analyse the bearing mechanism of mudstone with soft-hard alternant strata, the mudstone layer is choosed, and the interbedded mudstone models were built. The standard penetration test and shallow plate loading test have been studied. The results of test show that the relationship between standard penetration number and depth of burial is exponential relationship. The characteristic value of bearing capacity of interbedded mudstone is linearly related to the logarithm of standard penetration number. The bearing characteristic of interbedded mudstone is vulnerable to the unloading, disturbance and water content. Model formula of the relationship between the characteristic value of bearing capacity and the logarithm of blow count was verified with high reliability.

Abstract: Combined with the actual project that Rehabilitation and Strengthening of cleaning workshop at Longfeng refinery, three structural schemes of platforms are provided in this paper, and finally steel girder-diagonal brace scheme is selected through comparative analysis. Load, material and selection of section size for platform structural members are given. Deformation and internal force of structure are obtained by theory and PKPM analysis, the reasonableness that the member section is selected is verified. Connection design and specific structural measures are given, and finally the reinforcement design and checking for the carbon fiber of the original frame column is carried out, and these can provide reference for similar Retrofitting Project.

Abstract: Goafs formed in mine-out areas threat the underground mines owing to possibilities of rock burst and surface subsidence. This paper aims to discuss the feasibility, design and construction of waste rock backfill in abandoned stopes. Based on goafs distribution and stabilities in the White Bull Mine, rock backfill system with a total volume of 362,000 m³ in 8 gobs was designed and carried out. The system included technologically and economically feasible stopes, conveying equipments of tramcars, rock transfer by electric rakes, haulage network and mining workings. Field effects showed that rock backfill was applicable to control potential hazards. With rock filling, goaf utilization rates ranged from 60% to 70%, which helped to control adjacent rock movement, eliminate rock burst and surface subsidence. Additionally, backfill construction reduced the lift and transportation costs of rocks by about 50%, which further lowered the land usage of surface dumping.

Abstract: The seismic behaviors of tunnel lining passing through the fault are studied by means of large-scale shaking table tests under the load of Wolong-seismic wave. The model tunnel is installed into a model box with a length of 3.65 m, width of 1.5 m and height of 1.8 m. The sizes of model and prototype tunnel are designed by using the similar principles with a scale factor of 1:30. As the result shows, under the seismic force load, the tunnel lining has a delay of responding the seismic force when it crosses the faults geological belt. The time is 0.085seconds. Model box amplified table acceleration, the farther the distance from shaking table is, the more obvious amplification is. The seismic force load is horizontal, but the resistance applied by the faults geological belt is weak, resulting relative motion, collision, extrusion etc. so, the tunnel lining appears cracks. It is in accord with investigation conclusions of Wenchuan earthquake. Article also aims at some problems in the experiment such as: boundary effect, model box stiffness etc, and gives some suggestions.

Abstract: Due to the limited scientific level in forecasting seism, it is still not available to provide an accurate imminent prediction. As seism brings large amount of building destruction and casualties, taking effective anti-seismic measures to fortify and remodify buildings becomes the worldwide critical work in seism proofing and hazard reduction.

Abstract: Use Adina finite element software, established the finite element model of the the volume 10000m³LNG storage tank, against the concrete outer tank of full containment type LNG storage tank vertical seismic action seismic response analysis. Take acceleration seismic input method, select the four categories venue seismic waves, LNG storage tank stress analysis of vertical seismic action, come in different earthquake LNG storage tank outer tank equivalent stress, hoop stress and axial stress distribution.

Abstract: To research seismic performance of the strengthened masonry structure, the two stories masonry structure housing model with added ring-beams and tie-columns was designed and made in this paper. By inputting acceleration time-history curve of rarely earthquake of Intensity 7, the seismic response of acceleration, speed, restoring force and displacement of the strengthened masonry structure were obtained through the pseudo-dynamic test when rarely earthquake of Intensity 7 occurred. The reinforcement strain time-history curves of tie-columns root and beam-column junction were tested, then the restoring force-displacement curve of the structure was obtained. By method of pseudo-static test, the strengthened masonry structure of the ultimate limit bearing capacity, limit deformation were obtained, the cracking part and developing process were observed. Finally, comparing the data in this test with that test result of the ring-beams and tie-columns masonry structure designed based on current codes; analyzed seismic performance of the strengthened masonry structure when rarely earthquake of Intensity 7 occurred.

Abstract: The physical and mechanical parameters of surrounding rock have great influence on the stability of construction. In order to fully grasp the construction mechanical characteristics of surrounding rock highway tunnel under different mechanical parameters in Wudang schist tunnel, the in-situ measurement and numerical calculation are both used for sensitivity analysis of four mechanical parameters to the mechanical characteristics of surrounding rock-lining. The result shows that the sensitivity of E to deformation of surrounding tunnel is greatest, followed by μ, and both sensitivity far outweigh the one of C, φ. Sensitivity of C, φ on stress around the working face are larger than others. And sensitivities of these parameters to lining are different from stress and deformation. The sequences of sensitivity in a decreasing order, are the deformation modulus, the Poissons ratio, cohesion force and friction angle. However four parameters of sensitivity are not significant. These results provide reference on structure design, construction monitoring, disaster control in soft rock tunnel.

Abstract: In order to grasp the force performance and stress distribution of shaped pylon steel anchor box under the action of the cable tension, with a main span of 555m length of three towers cable-stayed and self-anchored suspension combined system bridge as the engineering background, through the APDL command stream parametric programming, the different finite element models of pylon steel anchor box is established by the spatial solid element and shell element, the mechanical properties of cable-pylon anchorage zone were studied under the most unfavorable load combination, considering the stress state and distribution characteristics of steel anchor box under different orthodontic force. The results showed that: under the most unfavorable combination of loads, the stress was concentrated at the position of the anchor plate and pressure plate using the initial strain mode; the calculation results of solid element and shell element were consistent by uniform loading mode, which could reflect the real stress state of steel anchor box, but the shell element corner contact area prone to stress calculation distortion.

Abstract: Due to the complicated theory of reliability analysis method and the high requirement of parameters statistics and model calculation, most reliability analysis methods are not conductive to engineering application. In order to solve this problem, a simplified method, can be used in slope stability analysis. The technique is based on factor of safety method. The procedure of applying this method in slope stability analysis is studied. The methods of calculating parameters standard deviation are summarized. Engineering application shows that Taylor series method is feasible and practical in slope stability analysis and it provides a new method for slope reliability analysis.