摘要
模袋法是解决上游法细粒尾矿堆坝难的一种新方法。为研究模袋法尾矿坝筑坝模袋的基本力学性能,采用与云南省某尾矿坝施工现场一样的土工布和尾砂,通过斜坡滑移、直剪、无侧限压缩试验,对固结不同时间的小尺寸尾矿坝筑坝模袋进行了摩擦和受压性能的试验研究。斜坡滑移试验表明,若含水率相对较低,则模袋间的摩擦系数较大;直剪试验测得固结8 d的模袋间内摩擦角约为28o,黏聚力约为40 k Pa;在无侧限压缩条件下,固结1 d和3 d的模袋在受压过程中,其弹性模量都表现为"大-小-大"的变化形式。由于土工布和尾砂的共同作用,模袋的极限抗压强度远大于单纯尾砂堆积体的极限抗压强度。当压应力达到模袋所能承受的极限荷载时,通常会在模袋底部靠近模袋边缘处发生土工布的撕裂破坏,采用主动土压力理论分析了发生破坏的原因。本试验研究可以为模袋法尾矿坝的实践提供理论指导。
Geofabriform method is a new method for constructing fine-grained tailings dam construction. To study the basicmechanical performance of tailings dam geofabriform, the frictional and compressive properties of small-scale tailings dam geofabriform are investigated by means of slope sliding test, direct shear test and unconfined compression test. The tailings dam geofabriform is made of geotextile and tailings sand, which both come from a construction site in Yunnan province. The slope sliding test of geofabriform shows that the coefficient of friction between the geofabriforms is larger when the moisture content of the geofabriform is lower. The internal friction angle and cohesion of the geofabriform consolidated for 8 days are around 28o and 40 k Pa respectively, based on the direct shear test. Under the unconfined compression condition, with the compression of the geofabriform consolidated for 1 day and 3 days, the tangent elastic modulus increases first, then decrease and finally increase again. Due to the combined effect of geotextile and tailings sand, the ultimate compressive strength of the geofabriform is much larger than that of the pure tailings sand. When compressive stress reaches the ultimate compressive strength of the tailings dam geofabriform, geotextile tearing often occurs at the bottom and close to the edge of the geofabriform, The failure mode is analyzed using the active earth pressure theory.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2016年第4期957-964,共8页
Rock and Soil Mechanics
基金
国家自然科学基金面上项目(No.51178012)
国家自然科学基金青年项目(No.51408127)
中央高校基本科研业务费专项资金(创新项目团队资助计划)(No.ZY20120103)
河北省高等学校科学研究计划项目(No.QN2015327)~~
关键词
斜坡滑移试验
直剪试验
无侧限压缩试验
尾矿坝筑坝模袋
摩擦系数
极限抗压强度
slope sliding test
direct shear test
unconfined compression test
tailings dam geofabriform
coefficient of friction
ultimate compressive strength
