Why do you want to use sand and soil and gravel soil after retaining wall
Reduce the side pressure of the soil, so that the force of the retaining wall and the design of the theory consistent,
After the wall with the permeability of the soil, the purpose of the lack of old mines to sink some of the rogue is a rapid drainage, reduce the rain, the formation of water pressure on the back of the wall to promote the role. Retaining the wall to set the drain hole, also for this purpose. Laying the drain hole, and each layer of the drain hole to set the impermeable clay layer is to make the water column is not too high, to avoid the water column is too high to increase the water pressure on the wall to promote the role and thus endanger the stability of the retaining wall. Unfortunately, now rough workmanship. Behind the wall is basically filled. Drain hole is not set, or set, but the bottom of the bottom impermeable clay layer is not set, or chaos, the drain hole blocked. So now the retaining wall is basically poor quality, short life.
Reduce the side pressure of the soil, so that the stress of the retaining wall and the design of the theory in line with the easy to seepage, to prevent damage to the retaining wall. To reduce the retaining wall active earth pressure, wall fill requirements: ① wall back to the wall to resist the strength of the wall mortar to 75% before the backfill. ② backfill material should be designed according to the design requirements of permeable materials such as gravel, gravel, slag, gravel soil, etc .; ③ wall backfill should be layered filling, each layer loose thickness should not exceed 200mm, And the strength of the compaction of the sampling frequency, compaction machinery can not reach the place should be small mechanical or manual repeated ramming dense; ④ back to the back of the wall should pay attention to set the anti-filter bag, anti-filter package must be permeable material Such as pebbles, gravel, etc.), particle size 20 ~ 30mm.
This is for drainage. Sandy soil and gravel soil usually require the filling of good water blocking clay, and then in the cohesive soil and sandy soil layer at the junction of the set of drainage pipes, or leave out of the exhaustive arc remnants of the old mixed. So that you can avoid the rainwater leakage on the retaining wall to produce erosion, endangering safety.
