Key Technique of Gas Sucking of "Three-Soft" Coal Bed and Its Application
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Research of anti-permeation mechanism of soft rock tunnel of shotcrete and its a nalogue experiment
In lingt of the anti-permeation performance problem of soft rock tunnel under the condition of shotcrete in glide structure area of West Henan,and from the basic theories of cube laws,combined with characteristics of laminar flow of ground water,and according to the different constructions condition,the analogue experiments of permeation properties of cementation plane are carried out;and homologous calculation formula are deduced.By comparison and analysis of the result,we can clearly understand the process and the mechanisms of interaction between various influence factors such as rock character,roughness,interface agent and large fluting,etc.It is concluded as follows:(1)as soft plane in constitution,permeation performance of cementation plane is far greater than that of rock mass and concrete;in the same,permeation performance of cementation plane of soft rock with coarse grain is also greater than that with fine grain;(2) restriction of roughness of rock mass,utilization of interface agent and set appropriate fluting on cementation plane can all increase its anti-permeation performance;and(3)load conditions of rock mass influence anti-permeation performance of cementation plane to a great extent.
On the use of the Hardening Soil Small Strain model in geotechnical practice
This article highlights the importance of using advanced constitutive soil models in numerical modelling as daily geotechnical practice. In this context, the Hardening Soil (HS) model is presented as the most advanced soil model implemented in the ZSoil finite element code. The article recalls the basic features of the HS model and it explains their role in numerical simulations. The role of pre-failure non-linear behaviour of soils is also discussed. An application of the HS model is illustrated on typical geotechnical problems such as retaining wall excavation, tunnel excavation and undrained loading followed by consolidation.