Chemical Grouting Co.
Chemical Grouting Co.
Umakoshi M.,Osaka University |
Miyamoto Y.,Osaka University |
Shimamura A.,Chemical Grouting Co. |
Nakata S.,Asahi Kasei Corporation |
Miyake T.,Nihon System Sekkei Architects and Engineers
AIJ Journal of Technology and Design | Year: 2017
This paper addresses the developing of response reduction device of a detached house during earthquake. Reduction devices are composed of shear key and improved composite soil material, which are arranged between the seismic-isolated layers. The mechanical properties of the improved composite soil material are investigated by laboratory tests. Then we confirm the hysteresis characteristics of this system by shaking table tests. Furthermore we investigate the response reduction effects of a house with this device during earthquake by analytical studies.
Tsutomu T.,Chemical Grouting Co. |
Hiroyuki A.,Chemical Grouting Co. |
Kazuhiko K.,Chemical Grouting Co.
Geotechnical Special Publication | Year: 2017
After a big earthquake hit east Japan, there is an increasing number of projects to reinforce aseismatic structure of buildings. Jet grouting is one of the effective methods to cater to the increasing needs. However, there are few cases applying jet grouting to the foundations of buildings because jet grouting is more expensive and more difficult to control the quality than mechanically mixing methods. To reduce the cost of jet grouting, we invented a new technique to construct rectangular-like columns instead of circular columns and set them in a row. This technique reduces the total number of columns, the production time and the production cost. Some field tests were conducted to construct the new columns. We succeeded in constructing the new columns and confirmed that the qualities and the construction efficiencies of the rectangular-like columns are not less than existing columns. © ASCE.
Goto H.,Kyoto University |
Tanaka N.,Chemical Grouting Co. |
Sawada S.,Kyoto University |
Inatani H.,Katsujima Co.
Soils and Foundations | Year: 2015
S-wave impedance is one of the most effective parameters used to study the ground motion amplification of soil deposits. We propose a new approach to measure the S-wave impedance of the uppermost material in surface ground layers. First, a circular disk is set on the ground surface, and it is vertically loaded by sinusoidal wave excitation. When the time series of the loading velocity is synchronized with the reaction force, the ratio of the reaction force to the loading velocity is proportional to the S-wave impedance. We then estimate the proportionality coefficient from numerical experiments and check its accuracy. The measurement error is estimated to be within 1% for the homogeneous half-space case. We also discuss the applicability of this new approach and its limitations on the basis of numerical experiments for inhomogeneous media: a two-layered medium and a one-dimensional (1-D) random medium. The proposed approach is effective for both cases if we select the appropriate circular disk size. © 2015 Japanese Geotechnical Society.
Bradley B.A.,University of Canterbury |
Bradley B.A.,Chuo University |
Araki K.,Chemical Grouting Co. |
Ishii T.,Chuo University |
Saitoh K.,Chuo University
Soil Dynamics and Earthquake Engineering | Year: 2013
This manuscript presents the results of an investigation into the effect of various configurations of lattice-shaped soil improvement on the seismic response of liquefiable soil deposits using 3-dimensional seismic effective stress analysis with an advanced constitutive model for sandy soils. The particular problem considered is based on the soil stratigraphy of the down-hole seismic array site at Port Island, Kobe, and the input ground motion recorded at this location in the 1995 Kobe earthquake. Nine different soil improvement geometries are considered by changing the number and wall thickness of improved soil cells for the site. For each of the different improvement geometries, the salient features of the ground response are presented, including: (i) peak surface acceleration, displacement and response spectra; (ii) excess pore pressure, stress path, and stress-strain response of the enclosed unimproved soil; and (iii) peak deformations of the improved soil, among others. Finally, the obtained results for all considered improvement geometries are summarised based on improved area ratio (RIA); improvement length-to-height ratio (RLH); and normalised construction cost (RCC). The results demonstrate the complexity of the seismic response and interaction between improved and enclosed liquefaction-susceptible native soils when subjected to strong ground shaking; the dependence on both the improved area and length-to-height ratios; as well as the wealth of insightful information that advanced effective stress analyses can provide for assessing the seismic response of such soil deposits. © 2013 Elsevier Ltd.
Ezaoui A.,Tokyo University of Science |
Tatsuoka F.,Tokyo University of Science |
Sano Y.,Kyosei kiko Co. |
Iguchi Y.,Chemical Grouting Co. |
And 3 more authors.
Soils and Foundations | Year: 2010
Ageing effects on the elasto-viscoplastic property of compacted moist cement-mixed granular material (GM) were evaluated by performing a series of non-standard drained triaxial compression (TC) tests. Two types of GM, crushed gravelly soil from a quarry and crushed concrete aggregate (i.e., a recycled material), were used. The specimens were produced by moist-compaction and then cured at constant water content under unstressed conditions for seven days. They were re-cured basically for two days under different stress states during otherwise drained TC loading at a constant strain rate. Yielding characteristics upon the restart of drained monotonic loading (ML) at a constant strain rate toward ultimate failure at the same or increased or decreased confining pressure were evaluated. The stress-strain behaviour before the stress state reaches the current yield locus is very stiff and highly reversible. Unlike elasto-plastic materials exhibiting no ageing effects, the yield locus expands during sustained loading at a fixed effective stress state due to not only yielding associated with creep deformation, controlled basically by the viscous property, but also ageing, controlled basically by time-elapsing. The shape and location of current yield locus depends on the location of the current stress state relative to the current ultimate failure envelope. The observed yield characteristics were analyzed based on a newly introduced interactive double-yield concept while in the framework of the non-linear three-component elasto-viscoplastic model that takes into account ageing effects as well as an interaction between ageing and inviscid yielding (and its potential decay by irreversible straining). The trends of stress-strain-time behaviour observed with the two types of cement-mixed GMs are essentially the same.
Komiya K.,Chiba Institute of Technology |
Yamanobe J.,Chemical Grouting Co. |
Endo M.,Chiba Institute of Technology |
Shiozawa T.,Chiba Institute of Technology
6th Japan-China Geotechnical Symposium, SJGS 2015 | Year: 2015
In situ soil-cement mixing is frequently used to minimize soil liquefaction, enhance soil strength and reduce soil permeability. For quality assurance purposes, drill core samples are taken from the soil-cement mixtures and unconfined compressive strength tests are carried out 28 days after mixing and placement, which may delay construction works. Clearly, there is a need to accurately predict the strength of soil-cement mixtures early. In this study, we prepared soil-cement mixtures with different proportions of clay, silt, sand, cement and water. The as-prepared specimens were subsequently cured at standard and various temperature, pressure and time conditions. We then compared the strength characteristics of the as-prepared soil-cement specimens. Unconfined compressive strength increases between 24 h and 48 h of accelerated curing; however, increasing the curing temperature does not lead to increases in strength. Compressive strength slightly increases with the curing pressure. Finally, the compressive strength depends on the cement and fines content and WTotal/C of the soil-cement mixtures.
Ishihara K.,Chuo University |
Araki K.,Chemical Grouting Co. |
Toshiyuki K.,Chemical Grouting Co.
Geotechnical, Geological and Earthquake Engineering | Year: 2014
Severe damage to houses, roads and buried pipelines caused by liquefaction of the ground was the characteristic feature of destruction at the time of the 2011 Great East Japan in 2011. Widespread areas along the Tokyo Bay and in the downstream reaches of the Tone River suffered the liquefaction-associated damage, despite of the distance as long as 450-500km from the epicenter of the quake. Typical examples of the damage are presented herein with reference to conditions of soil profiles. As a measure to gauge its destructiveness, the ground settlements resulting from liquefaction were calculated based on volume decrease characteristics of sandy soils and their outcome was compared with the settlements actually observed on the ground surface. There were several accounts by eye-witnesses and video-pictures which are tacitly indicative of advent of surface waves or sloshing-like movements of the ground surface. Although conceptionally, some interpretation is given to these new features of motions which have not been hitherto addressed. © Springer International Publishing Switzerland 2014.
Ishihara K.,Chuo University |
Kamata T.,Chemical Grouting Co.
Geotechnical, Geological and Earthquake Engineering | Year: 2015
Features of the 2011 earthquake in Japan are characterized by predominance of the ground failure due to liquefaction and scour of the ground caused by Tsunami. Unprecedented long duration of the shaking combined with large aftershocks have generated the worst situations resulting in the extensive damage due to liquefaction over the Tokyo Bay and the downstream plain areas of the Tone River 300 ~ 400 km distant away from the epicentral area. In this paper, focus is placed on the characteristic features in the occurrence of liquefaction and consequent damage in the area of the downstream reaches of the Tone River. © Springer International Publishing Switzerland 2015
Chemical Grouting Co. and EOS Remediation LLC | Date: 2014-03-19
A contaminated soil remediation method activates a microorganism in soil contaminated with a toxic chemical substance. The contaminant is decomposed by a biodegradation reaction of the microorganism. The method involves forming a boring hole reaching into contaminated soil. A rod whose end is provided with a jet device is inserted into the boring hole. The contaminated soil is cut in a manner forming a flat-plate area in which the soil is intermittently cut by a microorganism activator, and the soil and the microorganism activator are mixed, by jetting water and/or the microorganism activator from the jet device.
Yoshida H.,Chemical Grouting Co. |
Saito K.,Chuo University
Geotechnical Society of Singapore - International Symposium on Ground Improvement Technologies and Case Histories, ISGI'09 | Year: 2010
The main feature of cross jet grouting is to eject water from two nozzles attached to the jet monitor pipe. One jet directed upwards at some obliquity is made to meet with another jet directed downwards at a point of some distance from the jet monitor. By arranging the two jets in this way, the redial distance at which the energy of jetting is subsided is fixed, making the circumferential surface of the solidified column smooth, irrespective of existence of thinly stratified deposits of native soils. The mechanism of the cross jet grouting as above is first described briefly and two cases of its application are introduced in which it was used as a starting platform of the shield tunneling. Copyright © 2009 by Geotechnical Society of Singapore (GeoSS).