Due to severe damage on urban functions experienced in recent great earthquakes, higher seismic performances of infrastructures and industrial facilities, such as power plants or oil & gas plant, are preferred in seismic regions all over the world. However, this requires higher design seismic force and, therefore, provides higher construction costs. Performance-based seismic engineering is now an established technology for the more economical design of structures to resist earthquakes. We are proposing an economical method to reduce the seismic actions on the tank structures and shown its effectiveness on relatively stiff ground.
Discrete elements or continuous panels used as reinforcement to improve the overall performance of weak and/or large compressible soil masses. Ground improvement is defined as the controlled alteration of the state, nature or mass behavior of ground materials in order to achieve an intended satisfactory response to existing or projected environmental and engineering actions.
Deep Soil Mixing (DSM), RAS Column, Shallow Soil Mixing (SCM) and Jet Grouting method are effective for improvement of soil bearing capacity for building foundation, settlement prevention for foundation under future structures such as storage tank or LNG plant, and in-situ stabilization of contaminated soils for environmental remediation among other uses.
DSM is an in-situ soil mixing technology that mixes existing soil with cementitious materials using mixing shafts consisting of auger cutting heads, discontinuous auger flights, and mixing paddles. The mixing equipment varies from single to eight shaft configurations depending on the purpose of the deep mixing. The soil-cement produced generally has higher strength, less compressibility, and lower permeability than the native soils.
RAS Column is an advanced deep soil mixing method based on mechanical soil mixing technology to produce soil-cement column of 1.4m to 2.5m diameter. The mixing head is equipped with the counter rotation mechanism. This unique mechanism efficiently breaks and mixes in-situ soil with cement-based reagents, producing more homogenous and higher quality soil-cement columns.
SCM (Surface Compact Mixing) is a method to mechanically mix in-situ soil with cement powder or slurry. SCM provides two different mixing equipments, Rotary Blender and Bucket Mixing, to be selected depending on improvement objectives and depth. The unique mixing mechanism provides efficient, cost effective and quality improvement. Larger plant is not necessary. The mixing device can be attached to a local 0.8-1.9m3 excavator.
Jet Grouting is a technique of mixing in-situ soil with the energy of ultra-high pressure jet of slurry. A small-diameter rod drills down to the improvement bottom. Then the rod, while being withdrawn, jets the cement-base slurry and air to produce an improved column. Jet Grouting enables improvement closely contacted to or, in some cases, encompassing existing underground structures without causing damage to them.
DSM was designed to be installed into the dense Colma Sand 2’ to 5’. The General Contractor designed a temporary excavation support wall with wide flange beams with some beams on two foot centers, 45 beams total. This project is designed to support the structural concrete for the new US 101 highway, tunnels and bridges.