重塑和加筋后马兰黄土的强度试验研究

Experimental Study on Shear Strength of Disturbed and Reinforced Malan Loess

通过室内土工试验,测试庆阳地区马兰黄土在天然状态及风干、加湿、夯实、加筋等不同条件下的强度性质,为黄土窑洞稳定性分析提供必要的物理力学性质指标。结果表明:原状黄土的强度对含水量极为敏感,黄土含水量增大到饱和状态时粘聚力可从30kPa减少到0kPa;草泥的强度控制因素为筋土质量比,最佳质量比在3%～5%,拌合时稠度大于0.75,风干后的加筋土c值可达到178 kPa～201kPa,φ值可达50°～55°,破坏后草泥的残余强度依然保持比天然黄土高的水平,当垂直压力为100kPa时,草泥的抗剪强度可达天然黄土的4.5倍;夯实土的单轴极限抗压强度为2.09～3.46MPa。

Based on laboratory soil tests,writers analyzed shear strength of Malan-loess in Qingyang with the influence of physical indexes considered;the shear strength with different states includes natural state,dry state,wet state,compacted state and reinforced earth state.On the basis of laboratory tests data,the shear strength of Malan loess with the natural state is sensitive to water content.As the water content increases,the strength rapidly decreases from 30kPa to zero.The shear strength of the reinforced earth depends on mass ratio of reinforcement to loess.The best mass ratio is within 3% ～ 5% and liquidity index of reinforced earth is greater than 0.75.The shear strength index of the reinforced earth is c = 178 ～ 201kPa,φ = 50° ～ 55°.Residual strength is also higher than the loess.As σ = 100kPa,the shear strength of the reinforced earth is 4.5 multiples of the loess.Uniaxial stress peak strength of the compaction loess with the dry state is within 2.09 ～ 3.46MPa.