Reinforced sand cushion is a shallow treatment method for soft soil foundation of geogrid. After years of practice, it has been concluded that the effect of reinforced sand cushions is mostly focused on improving the bearing capacity of foundations.
Regarding the control effect of the reinforced sand cushion on the settlement of the foundation, it is mainly manifested in the following aspects:
(1) The geosynthetic reinforced sand-sand cushion can effectively reduce the settlement deformation of the soft soil foundation under the load of the upper embankment. Field test data shows that under the same conditions as the foundation soil layer and embankment filling, the effect of the geocell reinforced sand cushion is the best, followed by the double-layer geogrid reinforced sand cushion, and again Single-layer geogrid reinforced sand cushion. Compared with the unreinforced sand cushion scheme, the reinforced sand cushion scheme can reduce the settlement per unit height of the embankment by 10%~31.5%.
(2) In the sand cushion, increasing the number of geogrids laid from a single layer to a double layer can not only reduce the settlement and deformation of the soft soil foundation under the load of the upper embankment, but also reduce the tensile force of the geogrid . Compared with the single-layer geogrid-reinforced sand cushion scheme, the double-layer geogrid-reinforced sand cushion scheme can reduce the settlement volume per unit embankment height by 18.2%; the maximum tensile value of the geogrid per unit embankment height Can reduce 27.8% ~ 47.8%. Double-layer geogrid reinforced sand
In the cushion, the tensile force of the upper geogrid is 27.9% smaller than the tensile force of the lower geogrid.
(3) The geosynthetic reinforced sand cushion has a certain degree of homogenization of the base pressure. Compared with the unreinforced sand cushion scheme, the pressure ratio of the reinforced sand cushion scheme (reflects the degree of pressure concentration at the base of the embankment, which is the ratio of the average pressure near the center line of the embankment to the average pressure at the slope positions on both sides of the embankment) can be reduced 6. 1%~ 12. 1%.