Abstract:The factors affecting costrution quality of deep foundation bored pile are analyzed in terms of drilling, concreting and pile completion with some specific measures and practices proposed.

Abstract:The grout injection with ground fracturing after pile completion. mechanism of increasing the single-pile bearing capacity, equipment employed, operating method, technical parameters and operating considerations are described. A preliminary discussion is made on the injection volume and the injection pressure with ground fracturing.

Abstract:In order to ensure the pile foundation construction quality and reduce concreting cost, a variety of measures have been taken to prevent the borehole from enlarging and caving with focus on the related preventative measures and techno-economic benefits.

Abstract:The test principle 9 main performance parameters and design guideline of the ZP -1 drillpipe fatigue test bench are described with emphasis on the components and key design points of the mechanical drive system and the loading system of the test bench, as well as the experiments made on it.

Abstract:The rock bit diameter is calculated through determination of the extreme values with the calculation formula presented. Calculation and analysis of the diameters is made of the rock bits with/without.the axis offset.

Abstract:The operating principle, structural design, drilling tool features, as well as test, production trial. are described of the pneumatic jet-type reverse circulation tool of the central hollow DTH hammer.

Abstract:After the analysis of the acting forces in an double-acting hydro-hammer during the phases of acceleration of the harnmer, a mathematical model for computerized simulation is set up.

Abstract:The theoretical principle, for the selection of pulse electrical parameters during electro-plating are expounded; the rule of the effect of pulse electrical parameters on the Ni-W coat property is explored; andthe laboratory experiment on the pulse electro-plated bit is carried.

Abstract:The forming process of the foam mud cake is analysed, the forming mechanism of which lies in three aspects: change of the magnitude of the attraction and repelling forces between clay particles, effect of the polymer adsorption layer on the force between the particles, and three-phase moist periphery formed by air bubbles over the hole wall.

Abstract:Why it is difficult to drill water supply wells in the karst-developed area is analysed. Some problems concerning subsidence treatment, borehole deflection and caving prevention and well service life extension are discussed.

Abstract:The test and use of the controlled blasting of black powder in granite dimension stone production in Shangcheng County, Henan is described with working face production elements and reasonable blasting parameters recommended.