基于分形的绢云母片岩路基填筑利用技术研究

Research on Subgrade Filling Technology of Sericite Schist based on Fractal Theory

谷竹高速存在大量绢云母片岩,强度低,易崩解破碎,难压实,矿物成分以绿泥石、云母为主。引入分形理论,计算发现绢云母片岩粒料的分形维数随干湿循环次数增大而增大,最后达到稳定值约2.68。采用分形维数作为填筑利用指标,研究了CBR和回弹模量随分形维数的变化规律,结果表明CBR和回弹模量都随分形维数的增大先增大后减小,在分维数为2.65时分别达到最大值6.3%和35.8 MPa,因此建议碾压时将分维数控制在2.65。由于稳定分维数对应的CBR为3.6%、回弹模量为30.8 MPa,建议绢云母片岩只能用于下路堤的填筑。进行了现场碾压试验,通过分形维数随碾压遍数的关系图确定了松铺厚度为40cm,振动碾压6遍、静压2遍的碾压工艺。

; Large quantity sericite schist has been found along the Gucheng to Zhuxi Highway, whose main mineral composition are chlorite and mica with low strength, bad compaction characteristic and easy slacking property. By fractal theory calculation it is found that the fractal dimension of sericite schist aggregates increases with the times of dry-wet cycle, and finally tends to a stable value of 2.68. Choose fractal dimension as the subgrade filling index and then California bearing ratio（CBR） test and modulus of resilience test are carried out, the results show that CBR and modulus of resilience increase at first and then decreases with the increase of fractal dimension. When the fractal dimension is 2.65, CBR and modulus o{ resilience come to the maximum value at the same time, which are 6.3 and 35.8 MPa respectively. Based on the results, it is recommend to control the fractal dimension at 2.65 when rolling to compact subgrade. Because the CBR is 3.6 and modulus of resilience is 30.8 MPa at the stable fractal dimension, it is suggested that sericite schist aggregates can only be used in the lower embankment filling. Field compaction tests are carried out to get the relationship graph of fractal dimension and the rolling time. A rolling technology including thickness of uncompacted layer being 40cm, 2 times static rolling after 6 times vibration rolling is proposed.