Collapsible loess area roadbed foundation treatment structure and construction method

The invention discloses a collapsible loess area roadbed foundation treatment structure and a construction method. The structure comprises two water-stop curtains which are arranged side by side, a foundation reinforcing area and a waterproof pad layer, wherein the waterproof pad layer covers the foundation reinforcing area and the two water-stop curtains; one water-stop curtain faces towards the side surface of the other water-stop curtain, and the water-stop curtain and a slope toe of the roadbed are positioned in the same vertical plane. The construction method comprises the following steps: sampling to carry out an indoor geotechnical test of basic parameters; determining the height of the roadbed; flatlysurveying and setting out; carrying out impact rolling or heavy tamping reinforcement, thereby forming the roadbed reinforcing area; building the water stop curtains, top surfaces of which are parallel to the top surface of the roadbed reinforcing area; and building the waterproof pad layer which covers the roadbed reinforcing area and the water stop curtains, thereby completing the construction. The roadbed foundation treatment structure is applied to foundation treatment of the collapsible loess area low-grade highway subgrade with no great fill insulation to achieve the effects of processing the base with 6m compaction piles, so that the foundation soil is protected from being soaked, foundation post-construction settlement is controlled, roadbed body stability is guaranteed, the construction period is shortened, and the line operation safety is guaranteed.