针对西南地区某机场加筋边坡的离心模型试验,建立与离心试验尺寸一致的有限元数值模型,并采用考虑时间因素的Cvisc蠕变模型与M-C模型,模拟分级加载过程中离心模型的位移、土压力、筋材拉力随时间的发展和分布情况,并与离心模型试验结果进行比较。采用Cvisc模型研究了不同筋材长度,以及不同部位的筋材加密和筋材模量增加对加筋边坡的影响。研究结果表明:Cvisc蠕变模型能较好地描述变加速度加载的离心模型试验,引进时间因子能反映出不同时刻下离心模型的位移、土压力、筋材拉力;随着筋材长度的增加,潜在滑面后移,边坡稳定性提高;在1/3坡高处筋材拉力和水平位移最大,通过对1/6～1/2坡高范围内筋材加密或模量增加,是提高边坡稳定性最有效的方法,筋材加密效果优于筋材模量增加。
Abstract
A finite element numerical model was established based on the dimensions of the centrifugal test model for a reinforced slope at an airport in southwest China. By adopting the Cvisc creep model and M-C model under step loading, the development and distribution of the displacements, earth pressures and tensile forces of reinforcements of the centrifugal model with time were simulated, and the simulated results were compared with the centrifugal test results. The effects of different geogrid lengths, reduction of geogrid spacing, and modulus increment on reinforced slopes were also examined by using the Cvisc model. Results reveal that the Cvisc model well describes the centrifugal model test under variable acceleration loading, and the time factor reflects the displacement, earth pressure and tensile force of reinforcements of the centrifugal model at different instances. With the increase of reinforcement length, the potential sliding surface moved backward and the slope stability improved. The tensile force of reinforcements and horizontal displacement reached the maximum at 1/3 slope height. Reducing the spacing of the geogrid or increasing the modulus of the geogrid in the range of 1/6～1/2 slope height could be the most effective way of improving slope stability, and the effect of reducing the spacing of geogrid is better than that of increasing the modulus of geogrid.
关键词
加筋边坡 /
离心模型试验 /
数值模拟 /
蠕变模型 /
分级加载
Key words
reinforced slope /
centrifugal model test /
numerical simulation /
creep model /
step loading
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基金
中国民航机场建设集团有限公司科研项目(JSRDKYN201812)
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