Laying The Environment And The Impact Of The Freeze-thaw Cycle On The Mechamical Properties Of GCL

Common channel water use coefficient is only0.5, in water process in nearly half of water diversion for canal seepage loss, total water efficiency is very low. Geotechnical synthetic material impervious bentonite blanket (GCL) is a kind of efficient impervious membrane, permeability hydrostatic pressure can reach more than1.0MPa, permeability coefficient of5x10-11cm/s, can greatly improve the canal water utilization rate. With the GCL in engineering application shows good performance, the scope of its application more and more widespread. Mechanical properties of GCL indices on project quality, safety, function and other aspects have great influence. The channel field laying and indoor freezing and thawing cycles on mechanical properties of GCL was investigated, explores the main GCL aging factors and outer protective material for anti-aging effects, as well as thawing on mechanical properties of GCL influence research. The test for GCL of the application in arid and cold region of canal seepage control engineering provide the theoretical basis. This paper mainly in Hetao irrigation area channel laying GCL as the research object, using a mechanical test and analysis of GCL performance changes, to obtain some valuable conclusions and the results:(1) GCL in directly to the natural environment was exposed, tensile strength and strain with the laying of the extension of service time was decreased, the mechanical properties decrease greatly, average and annual the tensile strength decreased?.1%, the maximum strain decreases6.1%. Ultraviolet light to geotextile aging accelerated, laying in the bottom of ditch GCL because of cover soil and water as a protective layer, rather than laying on the canal side of the mechanical properties of GCL reduced the amplitude is very small, so do not need for processing is also, a very good aging resistance.(2) External protective material for B1, B3for GCL protective effect ion is very obvious, not only improves the mechanical properties of GCL, also slows the aging speed of GCL, GCL service life has a great influence on the GCL B2; outer protective material mechanical properties and aging resistance are improved, the more obvious enhanced resistance to aging ability, enhances the GCL structure stability.(3) The GCL absorption will occur after the slight shrinkage, this phenomenon makes the GCL after immersion, mechanical properties will be improved, increase in the range of3.14%～5.17%, and make the structure more closely (4) Cycle of freezing and thawing would make the GCL thickness increases, bentonite and expanded space increases, the GCL anti-seepage performance and reduce the structure compactness lower; many times after freezing and thawing cycles of frost heave effect of bentonite accumulated, the suture portion of the fiber fracture, reduce the geotextile connection between, on GCL anti seepage effect has a great influence on.(5) The test results show that strong damage resisting capability of GCL to resist deformation ability is weak; after many times of freezing and thawing. GCL mechanical properties and resistance to deformation of decline, drop15.52%～24.8%;4GCL2#optimal mechanical properties, due to the lower1#geotextile cannot meet the stress peak, the mechanical properties of the most unstable, so the1worst#mechanical properties.