Reconstruction and Expansion Project of Provincial Highway on Soft Subgrade

Reconstruction and Expansion Project of Provincial Highway on Soft Subgrade

(National Standard Textured 3D Honeycomb Geocell)

1. Project Overview

This is a reconstruction and expansion project of a provincial highway in China. The route contains extensive collapsible loess and silt. The original subgrade suffers significant settlement, and longitudinal cracks are highly prone to emerge at the joint between new and existing subgrade.

2. Adopted Specification

150mm High-textured 3D Honeycomb Geocell

3. Engineering Difficulties

Large stiffness difference exists between new and old subgrade; the thickness of subgrade cushion is restricted, and large-scale deep excavation and soil replacement are prohibited.

4. Solution

One layer of 3D honeycomb geocell reinforcement is laid at the bottom of subgrade to serve as a stiffness transition layer. Relying on the three-dimensional honeycomb confinement effect, crushed stone filler is integrated to form a composite rigid cushion.

5. Measured Project Results

- The thickness of subgrade cushion is reduced by 50%, cutting earth excavation volume.

- Effectively mitigate differential settlement between new and old subgrade; the occurrence of joint cracks drops sharply after opening to traffic.

- Soil shear strength increases by 2~3 times, eliminating pavement shifting and rutting defects.