路面结构S型复合土工材料排水系统性能分析

Analysis on performance of S-type geocomposite drainage system in pavement structure

针对传统的排水措施仅限于排除土体饱和条件下水分而无法排除非饱和状态下积水的问题,提出由水力传导层、防渗层和隔离层组成的S型复合排水材料新型路面结构排水系统.首先,开展室内模型试验,在人工降雨条件下监测基层和路基的基质吸力及体积含水量的变化;其次,采用数值软件模拟室内试验情况来验证模型的准确性;最后,探究水力传导层土工织物参数变化对其排水能力的影响.结果表明:新型路面排水系统能够快速有效地排除入渗水,试验过程中基层始终处于非饱和状态,路基土的吸力和体积含水量始终保持在初始值.随着Van Genuchten参数a值和饱和渗透率的增大,土工织物与土壤接触面形成的毛细屏障越弱,排水越快,建议a值取10 kPa左右,饱和渗透系数取0.01~0.10 m·s^(-1),而土工织物厚度对毛细屏障的影响并不显著,建议厚度取10~15 mm为宜.

The traditional drainage measures are limited to remove water under saturated condition but not under unsaturated condition.A new type of pavement drainage system with S-type geocomposite composed of hydraulic conductivity layer,impervious layer and isolation layer is proposed in this paper.First,indoor model tests were carried out to monitor the changes of matric suction and volumetric water content of the base and subgrade under artificial rainfall conditions.Secondly,the veracity of the model is verified by using numerical software to simulate the laboratory test.Finally,the influence of hydraulic conductivity geotextile parameters on its drainage capacity was investigated.The results show that the new type of pavement drainage system can remove the infiltration water quickly and effectively,the base is always in the unsaturated state during the test,and the suction force and volume water content of subgrade soil remain at the initial value.With the increase of Van Genuchten parameter a value and saturation permeability,the weaker the capillary barrier formed between geotextiles and the soil contact surface and the faster the drainage.It is recommended that a value should be about 10 kPa,and the saturation permeability coefficient should be within the range of 0.01-0.10 m·s^(-1).However,the thickness of geotextiles has no significant influence on the capillary barrier,so it is recommended that the thickness should be 10-15 mm.