Dynamic pressures against two adjacent retaining walls

Abstract

The dynamic pressures between two adjacent retaining walls were researched. Three tests of s o i l i n i t s loosest state and three tests of s o i l i n a dense state were conducted. The s o i l used was a dry s i l i c a sand. The acceleration of the dynamic tests was kept w i t h i n the range of 0.4 to 0.6'^ for frequencies ranging from 4 to 10 Hertz—Hfe} or cycles per second (cps) . The results were compared to a study done by a masters student on a single retaining wall. The s o i l settlement indicated a s o i l u p l i f t at seven cps f o r a l l t e s t s . Additional tests ruled out wall movement and s o i l migration. These tests did not rule out a natural frequency of the walls or of the s o i l being about seven cps, though. Also, a rocking motion of the test box at higher frequencies may have caused excess s e t t l i n g and the u p l i f t . Comparison of the output of pressure cells # 2 and # 3 show that the dynamic pressures against the adjacent walls, supporting a f i n i t e amount of s o i l ; is greater than against a single retaining w a l l , t h e o r e t i c a l l y supporting an i n f i n i t e amount of s o i l.