Overlapping tunnels will influence each other during construction stage,and will result in a series of problems such as ground subsidence controlling,particularly for watery and weak surrounding rocks in shallow depth.

Based on the shield boring of the exit section of Shiziyang tunnel on Guangzhou-Shenzhen-Hongkong passenger-dedicated railway,the authors present the selection and optimization of the boring parameters,the control measures,boring process,difficulties and the countermeasures of the large-diameter slurry shield in water-rich soft ground with shallow cover.

Survey of the mined-out section and water yield property of the small coal mine

Since the mining area is situated at runoff and discharge zones of Guozhuang karstic water system with strong water yield property,thus the hydrogeological condition is complex,average fault distribution is 91per km2,subsided column 60 per km2,so mine water disaster has many types.

By the use of 3D seismic prospecting exact locating,transient electromagnetic and electric sounding integrated interpretation carried out the detection of "scuttle" formed by hiatus of Quaternary aquifers' bottom clayey confining bed in Sima coalmine,Luan Coal Group,combined with regional hydrogeological features and mine hydrogeological condition interpreted water yield property.

10 stratum,water abundance characteristics and Yuemengou formation in carboniferous-permian is analysed in this paper.

Introduced how to determine water abundance characteristic parameter and dependence relati.

This paper deals with the relation of the petrological and electrical properties with the water abundance as well as the distribution law of the discharge water in the drilling hole,according to the hydrogeologic and logging informations in Zhangye basin of Hexi Corridor plain.