含软弱夹层的强风化泥岩强度及破坏模式试验研究

Experimental study on strength and failure mode of strongly weathered mudstone with weak interlayer

为研究软弱夹层对边坡失稳的影响,对含软弱夹层的岩体强度及破坏模式进行了理论和试验研究.采用某边坡钻孔芯样分别制备强风化泥岩、泥化夹层、含软弱夹层泥岩3种三轴试样,并进行三轴固结不排水剪试验.结合理论分析,对强风化泥岩、泥化夹层、含软弱夹层泥岩的强度和破坏模式进行了研究,揭示软弱夹层倾角、围压对试样强度和破坏模式的影响规律.结果表明:强风化泥岩、泥化夹层的应力应变曲线分别为应变软化型和应变硬化型;含软弱夹层的试样破坏时存在一个临界倾角范围,当软弱夹层的夹角在该范围内时破坏面发生在软弱夹层中,当夹角在该范围外时试样发生整体剪切破坏;围压超过0.4 MPa后,对含软弱夹层试样的破坏模式基本无影响.

In order to investigate the effects of weak interlayer on slope instability,theoretical and experimental studies on the strength and the failure mode of rock containing weak interlayer were conducted.Three types of triaxial specimens of strongly weathered mudstone,muddied interlayer,and mudstone with the weak interlayer were prepared by using the core specimens of a slope borehole,and the triaxial consolidation undrained shear tests were conducted,respectively.Combined with the theoretical analysis,the strengths and failure modes of the strongly weathered mudstone,the muddied interlayer and the mudstone with weak interlayer were studied,and the influence laws of the interlayer angle and the confining pressure on the strengths and failure modes of specimens were revealed.The results show that the stress-strain curves of the strongly weathered mudstone and the muddied interlayer are strain-softening type and strain-hardening type,respectively.There exists a critical inclination angle range for specimens containing the weak interlayer.When the interlayer angle is within the range,the failure surface occurs in the weak interlayer.When the interlayer angle is outside the range,specimens undergo global shear damage.When the confining pressure exceeds 0.4 MPa,the confining pressure has no effect on the failure mode of specimens containing the weak interlayer.