Filling mining is an effective way to settle the dilemma of “Three Down and One Above” in coal mining. Fly ash gangue can be used as filling materials with significant social, economic, environmental benefits. Using coarse fly base cementing material aggregate, orthogonal experiment paste was conducted this study. The range analysis performed for strength transportation requirements paste, optimum proportion determined by comprehensive balance method. In order verify effect, a dynamic...

In order to study the effect of fly ash content in cemented paste backfill (CPB) on its anti-sulfate erosion, apparent phenomenon, strength development, and hydration products change law CPB with different under long-term soaking 5% sodium sulfate solution were studied by macrotest microanalysis, addition, mechanism attack was analyzed combining a scanning electron microscope (SEM). The results indicated that environment (FCPB) mainly determined FCPB at times. early stage, formation...

In order to improve the fabrication robustness of inverse-designed devices that have complex topology structures, we propose an optimization technique, named as structure transformation (ST), transform structures into simple topologies contain less irregularly tiny features, sharp corners and boundary regions. The proposed ST based on a new alternately-implementing strategy optical performance modified curvature-constrained adjustment, effectively facilitates overall simplification devices,...

Coal mining operations in China are often threatened by the invasion of groundwater into panels. The most likely water disaster affecting safe operation coal mines is from Cenozoic porous aquifers alluvial plain areas flooding mine. problem will become very serious when mining-induced water-conducting fractured zone penetrates upwards aquifers, since it provides access for inflow mine working Therefore, crucial importance to determine zones predicting and preventing during mining. However,...

Abstract Vegetation is an important part of the natural environment and has resistance effects on overland runoff, which can effectively reduce hydraulic erosion. The effect vegetation stem diameter slope gradient flow thus worthy further study. influence three different gradients (s), diameters (d) 12 levels unit discharge (q) a was simulated to systematically study runoff. were found have significant Under same gradient, Darcy–Weisbach factor (f) increased with increase in diameter....

Abstract Soil erosion of farmland is a major issue faced by the agricultural industry. Control water-induced can be improved through simulation different configurations vegetation row direction to analyze effects directions RD on hydraulic characteristics flow. The were simulated and anisotropic influence flow was experimentally analyzed. Three groups with angles θ 15°, 45°, 90° respect FD configured. Experimental results show that caused variation in parameters velocity V, Reynolds number...

Dynamic time history analysis is a powerful and effective method to study the seismic response of tunnels, dynamic analyze tunnel in typical subway this paper. The results show that overall levelling will not affect too much, mainly related relative displacement ground around tunnel. internal force inclination have good linear relationship, can be used measure magnitude

The presence of orderly arranged rows and spacing crop vegetation increases the anisotropy Earth's surface, affects resistance surface to overland flow. However, few studies have addressed how arrangement In present study, we consider that flow has anisotropic attributes. We also performed a experiment using rigid simulated partially submerged vegetation. simulation replicated water in different directions over same surface. angles direction were as 15 °, 30 45 90 °. results show is composed...

The spatial variability of surface roughness can affect the overland flow processes. To accurately simulate processes watersheds, many theories have been developed which consider in roughness. Several claim that has anisotropic attributes, but there is little experimental evidence to support this claim. authors a hydraulic laboratory model land surfaces, and replicated water flows different directions over exact same surface. Two typical strip surfaces were simulated, Manning's coefficient...

Bioremediation is an environmentally friendly technology for the treatment of chromium-contaminated sites. Here, a hexavalent chromium [Cr(VI)]-resistant strain was isolated from oil-contaminated soil and designated as Bacillus sp. Y2-7 based on 16S rDNA sequence characterization. The effects various factors including inoculation dose, pH value, glucose concentration, temperature Cr(VI) removal rates were then evaluated. Based response surface methodology, optimal efficiency (above 90%)...

Practice teaching is an important segment of engineering education in university and has a significant effect on the comprehensive quality employment competitiveness graduates. Graduate field practice most part teaching. The graduate practice, which summary for four years' study, requires students to integrate basic theory with expertise, by thinking, analyzing solving problems independently, so as develop capability working independently scientific research. Based instruction graduation...

This study was conducted on the impact of carbonization reaction performance gangue–cemented paste backfill(GCPB). Tests were using a box with CO2 concentrations 0%,5%,and 10%. Each test for 3,7, and 28 days. We then uniaxial compressive strength(UCS)testing, as well X-ray diffraction(XRD)and scanning electron microscopy(SEM)analyses to explore effects mechanical properties GCPBs under varying concentrations. The results showed that before days, UCS GCPB increased time. higher concentration,...

Some hot environmental issues existed at present such as building waste dump, mine subsidence and unexploited coal under buildings, railways, water were analyzed, discussing the research status of waste, recycled aggregate, technology paste filling into goaf, then, feasibility goaf was proposed. Finally, orientation, strength, pumpability, stability, process design aggregate benefit evaluation analyzed.

Mine solid waste is the great potential resource, but unreasonable resource development leads to loss of and then does harm environment. There are many ways environmental management comprehensive utilization mine waste; recover useful elements, produce building materials, secondary energy recovery, fill pit collapse pit, paving, etc. However, problems exist such as backward technology, lack market competition due low value-added products, government support which remains be strengthened,...

Abstract To investigate the impact of curing environments on mechanical properties coal gangue cementation (CGC), various methods were established, including standard bag curing, natural sealing water and varying ages. By examining uniaxial compressive strength (UCS) stress–strain relationship CGC by applying axial loads, influence mechanism was analyzed in terms both physical chemical reactions. Furthermore, a mechanistic structural model established to illustrate environment CGC. The...

An increasing number of studies have shown that the seismic response shield tunnels differs from aboveground structures. While structures is mainly influenced by peak acceleration and frequency earthquake, more ground displacement due to surrounding soil layers. In this study, it not appropriate follow concept Dynamic time-history analysis a powerful effective method study in typical subway paper. The results show overall levelling tunnel will affect too much, related relative around tunnel....

It is a clear simplification to consider the tunnel lining as uniformly permeable. In reality, it more likely that there are specific leaks, associated with segmental joints. case of in situ concrete linings, construction joints can provide leakage paths, especially accounting for most water leakage. For transportation tunnels saturated soils below table, different settlements will lead ring offsets and changes joint opening near edges where gaskets located may significantly affect sealant...