Experimental Study On Mechanical Properties Of Argillaceous Dolomite With Pores Under Dry-wet Cycle Condition

Rock was a complex natural geological medium.Under the long-term geological and human action,various microscopic and macroscopic cracks(joints,holes,etc.)appear in the rock.Guizhou Province belonged to the plateau mountains,with frequent rainfall and abundant groundwater.Guizhou Province vigorously developed infrastructure.During the construction of rock mass,it was inevitable to encounter natural rock mass with holes.After repeated soaking and drying processes,the mechanical properties of rock with holes were seriously deteriorated.In order to solve the above problems,this paper takes the widely distributed argillaceous dolomite in Guizhou as the research object,combined with rock mechanics other theories and conducts dry-wet cycle tests on the rock with different inclination angles.Physical and mechanical characteristics and failure mechanism provided theoretical basis for engineering design and construction process.This paper mainly included the following:(1)Design and manufacture a device that can prepare rocks with different inclination angles of cavities.X-ray diffraction(XRD),X-ray fluorescence spectrometry(XRF),etc.are needed to determine the chemical composition of rocks.(2)In order to explore the dry-wet physical characteristics of argillaceous dolomite under different hole angles,the physical change law of the argillaceous dolomite was revealed through the indoor W-D cycles test of the hole rock.The results show that under the action of the W-D cycles,the P-wave velocity and quality of the rock samples are degraded to varying degrees and are time-sensitive,and the rock surface is getting rougher.(3)Through the uniaxial compression test of rocks with different cavities and angles under the action of W-D cycles,carry out research on the dry and wet mechanical characteristics of argillaceous dolomite under different pore angles.The results show that: under the action of drying and wetting cycles,the plastic stage of the stress-strain curve of the rock sample becomes more and more significant,the uniaxial compressive strength and elastic modulus gradually decrease,and the Poisson’s ratio increases slowly;The uniaxial compressive strength and elastic modulus also increased gradually.(4)The three-dimensional digital image technology(3D-DIC)system was used to track the crack propagation law and failure characteristics of porous rocks after drying and wetting cycles.The results showed that the initiation time of rock decreased with the increase of the dry-wet cycle.With the increase of the dip angle of the rock,the failure mode of the rock was closer to the axially parallel split failure.