Experimental Study On Physical-mechanical Characteristics And Damage Rule Of Thawed Luohe Sandstone

Based on half-freezing construction of shaft rich-water Luohe sandstone formation inXiao Zhuang, this paper studied on one freezing-thawing cycles of sandstone. With theory,lab-experiment and numerical, the physical-mechanical characteristics and damage rule ofthawed Luohe sandstone were studied. The main conclusions follow:(1)With uniaxial experiment, the mechanical properties and deformation were analyzedunder three condition of rich-water at normal temperature, freezing and thawing. The changelaw of uniaxial compressive strength and elastic modulus was also analyzed under differenttemperature. The results show: changing relation can be fitted by quadratic polynomial thatbetween freezing temperature and compressive strength, elastic modulus of sandstone.(2)Among the uniaxial compressive experiment, Acoustic emission parameters of failureprocess were simultaneously recorded. It shows: under the three conditions, deformation andAE activity have good correspondence and relationship between cumulative energy and countcurve of AE has more uniform law.(3)Analyzed the freezing-thawing damage mechanism of rock, based on the generalizedtheory of strain equality and the test results of uniaxial compressive experiment, the damageevolution equation and the corresponding damage stress-strain constitutive relation ofsandstone under different temperature was given. The calculation stress-strain relationship isconsistent with the test results.(4)Based on basic seepage law and the effective stress principle, coupled equationbetween seepage field and stress field and solution condition were obtained in shaftsurrounding rock. Under thawing of sandstone, the coupling relationship of seepage field andstress field was analyzed with finite element software in auxiliary shaft of Xiao Zhuang coal mine.