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复合衬垫系统广泛应用于垃圾卫生填埋场,是防止渗沥液污染物渗漏扩散的重要屏障。在垃圾重力及沉降作用下易造成斜坡上复合衬垫系统拉伸破坏或沿其界面产生滑移而失稳。目前,由于缺乏对复合衬垫系统内部剪力传递机理的认识,仍难完全解决以上两大岩土工程问题。因此,设计并采用复合衬垫系统大型斜坡模型试验装置开展了其内部剪力传递机理的研究。该装置通过砂袋加载模拟填埋过程,采用手拉葫芦为核心的滑移控制系统再现了土工膜/土工织物界面的渐进累积破坏过程。试验结果表明:当外部剪力小于峰值强度时,界面不会进入残余状态,上覆的土工合成材料锚固端的拉力也非常小;但当外部剪力超过界面峰值强度时,界面就会逐渐进入残余状态,并最终达到残余强度。同时,薄弱界面上覆的土工合成材料锚固端的拉力也显著增加,严重时甚至被完全拉断。
Composite liner system is widely used in landfill, which is an important barrier to prevent seepage and diffusion of pollutant leachate. Under the action of gravity and sedimentation of rubbish, it is easy to cause the composite liner system on the slope to stretch or rupture or slip along the interface to become unstable. At present, due to the lack of understanding of the internal shear transfer mechanism of the composite liner system, it is still difficult to completely solve the above two major geotechnical problems. Therefore, the design and application of large-scale slope model test device of composite liner system has been carried out to study its internal shear transfer mechanism. The device loads the simulated landfill process through the sand bag, and the gradual cumulative damage process of the geomembrane / geotextile interface is reproduced by adopting the slip control system with the hand chain hoist as the core. The experimental results show that when the external shear force is less than the peak strength, the interface will not enter the residual state, and the pulling force of the overlying geosynthetics at the anchoring end is also very small. However, when the external shear force exceeds the peak intensity of the interface, the interface will gradually enter the residual State, and finally reach the residual strength. At the same time, the pulling force of the anchoring end of the geosynthetic overlying the weak interface also increases significantly, even severely.