Recent Experiences of Reinforced Soil Retaining Structures in China - Reinforced Soil Engineering: Advances in Research and Practice - page 178

Figure 16 Cross section of foundation pit.

the bearing capacity of the foundation soil was equal to the applied vertical load
intensity, so that the pump house can't bear any horizontal earth pressure. The
plan included an empty “box-type” concrete retaining wall paralleled to box
foundation edge to bear the earth pressure of filled soil. The total budget of
frames, piles, and wall was 1,120,000 yuan.

4.6.1 The Scheme of Reinforced Earth

At first, the piping should be stopped and the former pit must be filled. The plan
was as follows:
1. Put 900m 2 of nonwoven geotextile on the bottom of the former pit and
cover a thickness of 1m of sand layer to prevent piping.
2. Control the quality of filled soil as foundation of pipes. However, the
wet season in the spring of 1994 made the soil heap up around the pit
with a high water content. The modified program was to put two
horizontal drain sand layers among the filled soils and construct a
preloading embankment (see Fig. 16). Based on the calculation of
consolidation, the degree of consolidation can reach 96% until 6
months later when the concrete pipes will be constructed.
3. Construction of three layers of sand mattress reinforced with woven
geotextile as the foundation of pipes, under

the preloading

embankment.
4. The edge of the preloading embankment was a temporary retaining
wall reinforced by woven geotextile and wrapped on the wall face by
means of soil bags. The temporary wall was the vertical slope for both
the preloading embankment and the new foundation pit.