Abstract:Causes of water well annualer Dermeabilitv reduction are described.Measures to improve perrne- ability reduction are discussed in terms of the drilling method,fluid properties,artificial infiltration layer,and well flushing,etc.

Abstract:Occurrences and forms of hydraulic fractures in drilling wells are analyzed for extraction of coalbed methane(CBM).The determination basis of dips,strikes and shapes of the fractures are presented.

Abstract:Effects of water/cement ratio,mixing water temperature and organic agents on sulphoaluminatecement slurry performance are discussed with the method to adjust its perforn1ance proposed.

Abstract:A study is put on the relationship between the thread taper and its strength,as well as the stressdistrtrbution law through a range of lab tensile,torsional and optical-elastic stresstests.

Abstract:How to select concrete pump for bored pile construction is discussed in terms of pump structure,performance and requirements of bored pile construction on pump.The method to determine pump pressure by using of pump pressure characteristic diagram is described.Operation of the pump is introduced.

Abstract:The problems in the blasting of the short terrace tunneling in Shijianling Tunnel are analyzed.Awhole section tunneling blasting scheme is proposed on condition that the simple self- made drilling platform hasbeen used for whole section tunneling,Rational and available smooth blasting parameters are determined by thedesign of engineering analogy and field practice. Also discussed ls the method of millisecond relay ignition bynonelectric millisecond detonation outside holes so as to increase the number of the relays of detonators in tunnel-mg.

Abstract:引起烟囱水塔等细高型建筑物爆破倾倒时的后座现象有两大因素，即爆破切口长度和切口形状。并在控爆实践中提出了有效防止后座现象的确定方法和计算公式。

Abstract:This paper introduces different methods of pile driving,including using of drilling devices andpile hammers in Germany.