Soil Mixing Wall Research Articles

Study on Underground Water Sealing Treatment by the Use of Soil Mixing Wall in Damsite

Study on Underground Water Sealing Treatment by the Use of Soil Mixing Wall in Damsite

じん性能を付加した繊維補強ソイルセメント固化体の強度特性

This study focused on strength properties of fiber-reinforced soil cement (hereafter FRSC), which contained PVA (polyvinyl alcohol) fiber with 14μm diameter, 8mm length, and 0.6% volume fraction. We conducted two series of experiments, mixing tests with different soil cement matrix mix proportions, and execution tests of FRSC column. As the result of material strength tests for laboratory mixed samples, improvement in tensile strength was the most significant: about four times higher than that of plain soil cement (hereafter SC). And modulus of rupture of FRSC also increased 2-3 times above those of SC. Execution test was conducted at loamy ground, using the machine for Soil Mixing Wall Method, and material strength tests of sampling specimen were carried out. Direction dependence of modulus of rupture was found, but executed FRSC column had approximately high-performance ductility close to that of laboratory mixed samples.

Field Behavior of Excavation Stabilized by Deep Soil Mixing

This paper describes the performance of a tiedback excavation with a soil mixed wall in Boston where underlying marine clay was stabilized by deep soil mixing (DSM) and jet grouting. Lateral and vertical soil displacements, soil strains, and tieback loads are evaluated. The interaction between the retained soil and a reinforced concrete box culvert, supported on drilled shafts, is described. Piezometer measurements behind the wall are summarized. They show pore-water pressures in marine clay substantially less than the hydrostatic pressures assumed in design.

Deep and high in Hawaii : G. Y. K. Chock, Civil Engineering — ASCE, 65(11), 1995, pp 42–45

The First Hawaiian Center, headquarters of the First Hawaiian Bank, will be the tallest building in Hawaii when it is completed in 1996. The unusual design, by architects Cohn Pedersen Fox, posed some structural engineering constraints. Wind and seismic loads were also considered in the design. Hawaii has had several major hurricanes and this was a major consideration. The design called for an unusual sail plan and for eccentric placement of the elevator core. Designers developed six different building configurations, and cost estimation and value engineering was performed on all of these. The structural engineers decided to submit several designs to a dynamic structural tuning to ensure safety as well as occupant comfort in the building. The final design selected was mixed construction system with a concrete basement and an all-steel framed superstructure. The author enumerates the reasons for the final selection. The building's foundation was also a challenge, because of the basement depth of 45 ft below mean sea level and the marine environment. A perimeter soil-mixed wall was installed and dewatering proceeded while the five-story basement and the tower structure were being constructed.

特集 都市における応用地質学の課題 地下構造物の地下水復水対策工とその効果

Recently, constructions of highway in a city have been built in semi-groundstyle as one of environmental methods against noise pollution. However, in some cases, these constructions can influence harmfully on the groundwater environmental protection, because they intercept the groundwater flow system.Semi-underground highway of Touhoku Line in Nerima section intercepted the aquifer, which was expected that the maximum water table rose 3m at up-stream and went down 2m at down-stream. Therefore, groundwater recovering countermeasure was necessary.Based on the results of field surveying observation and numerical simulation, this paper explains the groundwater recovering countermeasure and its effects which can respond well to the underground structure, hydrogeological conditions and the variations of water table.As results, we took following steps by considering both situations in nature and in heavy rain.(1) Walls used for S. M. W (Soil Mixing Wall) in up-stream and down-stream were cut 3m and 3.5 m depth from the ground surface, respectively;(2) Underdrain was constructed;(3) The connected conducts with 200mm in diameter were installed in every 50m; and(4) Discharges in downstream was conducted through infiltration boxes or recharging wells set every 50m.During the construction, maximum water table rose in 1.5m at up-stream and went down in 1m at downstream, respectively. After this countermeasure was built, the water table is stabilized at the same depth as before. Therefore, the effect of engineerings for recovering groundwater system is obviously satisfactory.