Experimental Study On Physical Weathering Of Basalt In Wudalianchi, Heilongjiang Province

At the time of volcanic eruption,the flowing lava formed various lava morphologies composed of basalt during the cooling process,which has the dual value of aesthetic appreciation and scientific research.These relics are degraded by weathering due to various environmental factors(such as water and temperature)due to prolonged exposure to the outdoors.The paper aims to evaluate the weathering behavior and degree of basalt from Wudalianchi volcanic district.Laboratory experiments,namely,rain test(R-T),heat-cool(HC),and freeze-thaw(F-T),were carried out to simulate basalt's weathering process.The main research work and achievements of this paper are as follows:(1)The paper analyzed temperature changes of lava during cooling.A 3D model of hornito was established and the thermal tress distribution was calculated through numerical simulation.This paper point out that vertical cracks are the primary cracks produced during the forming process of hornito.(2)The mineral composition and chemical composition of basalt were obtained through microscopic observation of flakes and X-ray diffraction(XRD).The physical properties and mechanical strength of basalt were tested in accordance with relevant specifications,and the density,porosity,pore size distribution,water absorption,Sonic velocity,and dynamic elastic modulus,uniaxial compressive strength,elastic modulus,and Poisson's ratio were obtained.(3)Laboratory experiments,namely,rain test(R-T),heat-cool(H-C),and freeze-thaw(FT),were carried out to simulate basalt's weathering process.Basalt samples were subjected to 10 cycles of R-T,375 cycles of H-C,100 cycles of F-T,respectively.After different numbers of cycles,weight loss,sonic velocity,and 3D surface topography were tested.All treatments(i.e.R-T,H-C and F-T)led to weight loss of specimens.The specimens deteriorated in different forms.