剪切速率和材料特性对筋-土界面抗剪强度的影响

土工合成材料与填料之间的界面强度参数是加筋-土工程设计的关键技术指标,筋-土界面的直剪试验和拉拔试验在界面剪切特性试验研究中应用最为广泛。利用土工格栅、土工织物与砂土的直剪试验和拉拔试验,研究了剪切速率和筋材性质对筋-土界面强度的影响。研究结果表明,当剪切速率不超过一定界限(如7.0mm/min)时,其对直剪试验结果的影响可以忽略;筋-土界面强度受加筋材料及砂土特性的影响,双向聚丙烯土工格栅和土工织物与砂土之间的内摩擦角与纯砂接近,界面强度较高,而玻纤格栅因其延伸率低和网格尺寸较小,与砂土的界面强度比较低。

Effects of shear rate and material properties on shear strength of geosynthetic-soil interface

The strength parameters of the inferface between geosynthetics and soils are the key technical factors for the design of reinforced-soil engineering. The direct shear test and pullout test are widely used in characterizing interaction between geosynthetics and soils by experimental methods. The pullout tests of geotextile/geogrid buried in quartz sand and the direct shear test between geotextile/geogrid and sand were carried out; the attempt is made to explore the influence of shear rate and reinforcement material properties on the interface shear strength. The results indicate that the effect of shear rate on the interface direct shear strength could be ignored when the rate is not higher than a limited value ( such as 7.0 mm/min). The interface strength is influenced by the types and characteristics of reinforcement material; the internal friction angles of interface between geotextile/bidirectional polypropylene geogrid and sand are similar to that of clear sand; but a lower internal friction angle value between fiberglass geogrid and sand was gotten as its lower elongation rate and the smaller grid sizes.