滇中昆阳群因民角砾岩及其成因

“因民角砾岩”的成因问题是一个争论已久的问题，至今仍未有统一的认识。笔者通过对滇中和东川地区“因民角砾岩”的观察，对其进行了详细的分类。根据其成因划分为沉积砾岩（包括复成分砾岩、滑塌角砾岩与石英砾岩）、火山角砾岩与构造角砾岩（包括断层角砾岩与水力张裂角砾岩）。对“因民角砾岩”成因的研究，特别是“水力张裂角砾岩”的提出，对于解决昆阳群的地层层序，了解滇中元古宙地壳演化以及进一步找矿都具有重要的意义。

DEM simulation of confining pressure effects on crack opening displacement in hydraulic fracturing

Hydraulic fracture is one of the key methods in well stimulation to increase production of oil and gas.Crack Opening Displacement(COD) is of great importance in this method since it is in direct relation with permeability and production rate.In this paper COD is measured by a distinct element model which has been validated by an exact solution.A comprehensive study has been performed on confining pressure effect on COD which is neglected in the analytical solution.Numerical results showed that confining pressure considerably affects COD.A multi-parameter regression(considering effect of confining pressure,rock mass properties and fluid pressure) was performed on numerical results which resulted in an equation.The proposed equation considers the effect of confining pressure and its results are in good agreement with numerical results.