Numerical Simulation of Gas-Water Dual Media in the Process of Coal Seam Hydraulic Extrusion

Assuming that the flow of water and gas in the coal seam fracture system to follow Darcy flow law, according to multiphase fluid flow mechanics and porous media fluid mechanics theory, this paper establishes gas-water dual media in the coal seam hydraulic extrusion coupled seepage model. Make use of this model simulates the main technical parameter injection pressure of the coal seam hydraulic extrusion, and compared to actual injection pressure of Huai river mining area, the results are in agreement. This model provides a reference to optimize the main techinical parameters of the coal seam hydraulic extrusion.

Orthogonal Design Optional Method of the Numerical Theory for the Hydraulic Squeeze Parameters

To apply the orthogonal design to confirm the optimal combination parameter of hydraulic squeeze is one good method for the coal seam in a state of stable geological factors. But if so the effect of injection meets uncertainly the requirement of the project in pace with advancement of the hydraulic squeeze measure and changing of the geological factors.In view of this situation and the characteristic of qualitative variable as well as quantitative variable of the geological factors affecting hydraulic squeeze. Put forward the application of numerical theory on the basis of optimization study of orthogonal design to confirm the optimal combination of the technical parameters of hydraulic extrusion when geological factors is in precarious state and then proceed optimization study.

Intrusive and extrusive (micro)melange couplets as distal effects of tidal pumping by a marine ice sheet

Microscopic soft-sediment deformation structures in a 30 × 25 × 12 mm hand specimen of glaciogenic silty mudstone from the Permo-Carboniferous Dwyka Formation of northern Natal in South Africa are illustrated by serial sections. The processes these structures imply are interpreted using palinspastically restored sections and isopachytes reconstructed from them. The sedimentation of silts, muds, and microrhythmites is found to have been punctuated by episodes of hydraulic activity which resulted in thirteen bodies with the mixed fabrics of micromelanges. These are divisible into five melange types: (1) subconcordant intrusive; (2) disconcordant intrusive; (3) subconcordant extrusive; (4) near-surface with asymmetric internal structures, and (5) conformable near-surface with internal structures symmetric about the palaeovertical.Remarkable similarities between isopachs for pairs of micromelanges at different levels in the specimen suggest that intrusive melanges at depth fed contemporaneous extrusive melanges on the sea floor. Each couplet of melanges with matched isopachs is linked by faults which are interpreted as having acted as hydraulic vents despite only parts of them being infilled by intrusive melange. A significant proportion of the succession could consist of sediment recycled from depth by hydraulic extrusion. Repeated hydraulic intrusions along, and extrusions from, the same disturbed interface suggest that this interface acted as the distal leaking end of one of the hydraulic sills recently described by von Brunn & Talbot (1986). Pulses of pressurized water were transmitted through a prograding marine slope of quickclay by the tidal pumping of a marine ice sheet periodically grounding upslope.The results of this analysis are extrapolated to processes operative in subduction complexes. All four fabrics described from large-scale hydraulic melanges in modern and ancient accretionary prisms are matched on a much smaller scale in our sample from a proglacial submarine slope. Dismemberment by faults is the only fabric element described from accretionary complexes which is missing from the micro-analogues described here.

A Load Calibration Technique for Use on Large Industrial Presses and Small Testing Machines

A load calibration technique based on the plastic deformation of a ring specimen is described. The method is applicable to any size press at loads up to full capacity. The method consists of determining the true flow stress of a heat of material by compression of small ring specimens on a calibrated test machine and treating the geometric change of the ring mathematically. Larger rings from the same heat of material are then deformed in large industrial presses or smaller testing machines which are to be calibrated. The geometric changes in the ring specimen and the previously determined flow stress are treated by the same mathematical analysis to determine the deformation pressure and thus the deformation load. A comparison is made of the calibration from the ring cell with other calibrations already determined on a mechanical crank press and a hydraulic extrusion press. The ring cell is shown to yield highly accurate load information.