聚丙烯纤维加筋灰土的三轴强度特性

Triaxial shear strength characteristics of lime-soil reinforced with polypropylene fiber inclusions

加筋技术作为20世纪一项重大发明,广泛运用于挡土墙、堤坝、桥台、护坡等工程中。加筋技术的快速发展推动了加筋材料的快速演变,催生了土工织物、土工格栅、土工格室等一大批土工合成材料,但加筋材料有一弱点:即筋材与填料间容易出现潜在破坏面。过去填料使用的是黏土、砂土,其强度都比较稳定,时间对其强度的影响极小。对于灰土这一类材料,其强度受时间影响较大,是否适于作为加筋土填料需进行研究。选取聚丙烯纤维作为加筋材料,研究了聚丙烯纤维加筋灰土的强度与变形特性。试验中,将3种不同百分比(0.05%,0.15%和0.25%)的聚丙烯纤维分别掺入到灰土比为1:9,2:8,3:7的灰土试样中,配制试样。通过三轴试验研究了不同纤维加筋率、不同灰土比、不同龄期及不同围压对加筋灰土的影响。试验结果表明:与普通的灰土相比,聚丙烯纤维加筋灰土其峰值偏应力和抗剪强度均有不同幅度提高。

As an important invention,reinforced soils have been using widely in retaining walls,dams,bridge works,slopes,etc.The rapid growth of reinforced soils has been pushing the development of reinforced materials,such as geotextile,geogrid,geocell and so on.These geotechnical materials have weak point： potential failure surface is liable to appear.In the past,clay and sand were used as stuffing,their strengths are stable and less affected by the time.The lime-soils strength has much to do with the time,if it is used as filling material,is it suitable？ In this paper,an experiment program is carried out to study the strength and deformation of lime-soil reinforced with polypropylene fiber inclusions.Three percentages of polypropylene fiber contents,i.e.0.05%,0.15% and 0.25% by weight of lime-soil are randomly included into the one-nine,two-eight and three-seven lime-soils.Based on triaxial compression tests,the influences of different reinforced rates,different lime contents,different curing ages and different confining pressures,are studied.From the results of tests,it is shown that the peak deviator stress and shear strength at failure increased at different ranges compared to the conventional lime-soil.