Filter layer is directly related to underground trench drainage, and the current design criterion for filter layer is relatively coarse, the classification of soil is not considered, filter layer thickness and the uniformity of filter material are not required, and so the current design criterion can not meet the needs of underground trench design of loess donga. Aimed at underground trench characteristic of loess donga, based on subgrade functional mode, this paper puts forward equivalent aggregate size , evenness control standards, the number of filter layers and thickness determination principle.
Layer Thickness Determination