摘要:
风化会使岩石材料孔隙发育、严重影响其工程性能,研究风化作用对花岗岩力学特性及抗侵彻性能的影响,对侵彻战斗部毁伤效能评估及地下工程防护能力分析具有重要意义。选用两种不同风化程度的花岗岩为研究对象,基于试验法系统分析其物理特性、静/动态压缩性能及抗侵彻性能的差异。结果表明:风化作用会造成花岗岩黑云母和斜长石含量降低,孔隙率增加、内部组织变松散,缺陷加剧;风化作用将导致花岗岩抗压强度劣化、应变率效应降低,破坏模式从脆性破坏向弱剪切破坏转变;三轴围压作用下,两种花岗岩随围压增大,静、动态抗压强度显著提升,且中风化花岗岩抗压强度对围压作用更为敏感;高速侵彻条件下(即873m/s~1040m/s),两种风化花岗岩抗侵彻性能差异较小,无量纲侵深不超过3倍弹长,并且岩石靶中不存在明显侵彻弹道区,存在明显的压碎区、约为弹径5~8倍。
Abstract:
Weathering effect can lead to the development of pores in rock material, which affects its engineering properties seriously. Therefore, studying the influence of weathering effect on the mechanical properties and anti-penetration properties of granite is of great significance to evaluate the damage effectiveness of penetration warheads and analyze the protection capability of underground facilities. The two kinds of granite with different weathering degrees were selected to systematically investigate their physical properties, static/dynamic compressive properties and anti-penetration properties with the experiment methods, such as the X ray diffraction (XRD) test, the static uniaxial compression test, the static triaxial compression test, the dynamic uniaxial compression test, the dynamic triaxial compression test and the two-stage light gas gun test. Finally, the results indicate that weathering effect can cause decrease of biotite and microcline, increase of porosity, loose internal structure, and obvious defects in granite, based on the X ray diffraction analysis technique. Besides, weathering effect also can lead to deterioration in granite’s compressive strength, weakened strain rate effect, and the shift of the failure mode from brittle failure to weak shear failure. Under static and dynamic triaxial compression, as for the two kinds of weathered granite, static and dynamic compressive strength rises significantly with confining pressure increasing meanwhile moderately weathered granite is more sensitive to confining pressure, compared with the slightly weathered granite. Under the condition of high-speed penetration, the speed varying from 873m/s to 1040m/s, there is a little difference in anti-penetration performance for the two kinds of weathered granite, in which case both of the non-dimensional penetration depths are generally no more than 3 times the length of the projectiles. Moreover, no obvious penetration trajectory zones exit in weathered granite targets while there are obvious crushed zones around the projectiles, the length of which can reach up to 5~8 times the diameter of the projectiles.