Disintegration Evolution Mechanism Of Argillaceous Slate Under Water-rich Condition

Slate has a widespread distribution in China.It mainly distributes in ten regions included of Yunnan Province,Hubei Province,and Guizhou Province etc.Slate is a typical layered rock,with dense lithology,impalpable structure and cryptocrystalline texture,usually with dense slate cleavage,the plate surface smooth,palimpsest mud structure.Its protolith may be shale,mudstone and tuff.The uniaxial compressive stress can reach 100?200MPa in an environment without water,and it can be classified as hard rock.However,under the action of water,its microstructure changes significantly,and then the water-physical property and mechanical property of rock reduce.For example,water can permeate into the rock through kinds of cracks,then the clay minerals react physically and chemically the water,and adhesion stress between layers reduce.And that is the basis of softening,swelling and disintegration.As for argillaceous slate,it will disintegrate more acutely because of dense slate cleavage and lots of clay minerals.In recent decades,the country's economy has grown by leaps and bounds.The national infrastructure is constantly improved.The disintegration of argillaceous slate under the action of water hinder all kinds of engineering project in the area of argillaceous slate.Works in this paper are all based on the target of quantitative analysis to disintegration of argillaceous slate.The experiments include Disintegration test,X-ray diffraction test and Scanning electron microscopy test and Nuclear magnetic resonance test.Then we concluded the macro and micro mechanism of disintegration of argillaceous slate on the basis of experiment works.At last,the nonlinear dynamics system model of argillaceous slate disintegration under water-rich condition was established,which defines the relationship between characteristics of disintegration,microstructure and area of fracture surface.By the above study,we got series of conclusion as following:a.disintegration resistance index attained the minimum value of 94.62% after dipped in water 9 days;during the dipping for 11?30 days,the disintegration resistance index stabilized at 94.93%.b.the disintegration showed three stages in the dipping progress: during the dipping for 0?9 days,the disintegration did not appear;during the dipping for 11?15 days,cracks began to develop,slime could be seen on the rock face;during the dipping for 20?30 days,cracks grew significantly and expanded significantly.c.during the time of immersion in water,cracks developed along the direction of slate cleavage,which showed obvious anisotropy and indicated that gathered between slate cleavage.d.the main mineral components of argillaceous slate are quartz,feldspar,calcite and illite.The minerals are arranged in a scale and corpuscular orientation,forming a local flake.Under the immersion of water,the argillaceous cement lost its strength,then the cracks grew.Along the cracks developing and joining together,we saw the macrocracks developed,at last the disintegration happened.e.on the basis of the macro and micro mechanism of disintegration of argillaceous slate,the nonlinear dynamical system model of argillaceous slate under water-rich condition was established,which defines the relationship between characteristics of disintegration,microstructure and area of fracture surface.Results showed that the predicted value has much similarities with the observed value,and thus the nonlinear dynamical system model can quantitively describe the disintegration of argillaceous slate under water-rich condition.