排序方式: 共有18条查询结果,搜索用时 15 毫秒
1.
Performance of Mortar and Chemical Grout Injection into Surrounding Soil When Slurry Pipe-jacking Method is Used 总被引:1,自引:0,他引:1
Hideki Shimada Takashi Sasaoka Saeid Khazaei Yasuhiro Yoshida Kikuo Matsui 《Geotechnical and Geological Engineering》2006,24(1):57-77
Small-diameter shallow tunnels are often being built by using the slurry pipe-jacking method. This system involves the pushing
or thrusting of a drivage machine and concrete pipes into the ground. Chemical grout injection into the surrounding soil around
the tunnel is carried out after the drivage and pushing processes are finished. The purpose of the chemical grout injection
is to maintain permanent stability of the surrounding soil. However, the behavior of the chemical grouting material in the
surrounding soil around the tunnel and the amount of optimum injection is not clearly understood. From these points of view,
this paper discusses the performance of the chemical grouting material, when it is injected into the surrounding soil around
the tunnel, by means of 2-D Eulerian–Lagrangian seepage analysis. Moreover, the effectiveness of the chemical grout injection
was evaluated by using the non-linear finite element method. This investigation show when the range of the grouted zone is
designed; it is necessary that the relationship between Young’s modulus of the soil/grouted zone and the confining stress
be taken into consideration in order to establish effective, economical and safe chemical grout injection system. Understanding
the performance of the seepage/dispersion behavior of the chemical grout and the characteristics of soil/ grouted zone is
also important. 相似文献
2.
Monitoring of Over Cutting Area and Lubrication Distribution in a Large Slurry Pipe Jacking Operation 总被引:1,自引:0,他引:1
Saeid Khazaei Hideki Shimada Takashi Kawai Junichi Yotsumoto Kikuo Matsui 《Geotechnical and Geological Engineering》2006,24(3):735-755
Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of the underground pipelines
of sewage systems. Pipe jacking, in its traditional form, has occasionally been used for short railways, roads, rivers, and
other projects. Basically the system involves the pushing or thrusting of concrete pipes into the ground by a number of jacks.
In slurry pipe jacking, during the pushing process, mud slurry and lubricant are injected into the face and the over cutting
area that is between the concrete pipes and the surrounding soil. Next, the slurry fills voids and the soil stabilizes due
to the created slurry cake around the pipes. Fillings also reduce the jacking force or thrust during operation. When the drivage
and pushing processes are finished, a mortar injection into the over cutting area is carried out in order to maintain permanent
stability of the surrounding soil and the over cutting area. Successful lubrication around the pipes is extremely important
in a large diameter slurry pipe jacking operation.
Control of lubrication and gaps between pipes and soil can prevent hazards such as surface settlement and increases in thrust.
Also, to find voids around the pipes after the jacking process, in order to inject mortar for permanent stabilizing, an investigation
around the pipes is necessary. To meet these aims, this paper is concerned with the utilization of known methods such as the
GPR (Ground Penetrating Radar) system and borehole camera to maintain control of the over cutting area and lubricant distribution
around the pipes during a site investigation. From this point of view, experiments were carried out during a tunnel construction
using one of the largest cases of slurry pipe jacking in Fujisawa city, Japan. The advantages and disadvantages of each system
were clarified during the tests. 相似文献
3.
针对IPCC评估报告中海洋碳循环的疑问——δ13C收支平衡法的验证 总被引:2,自引:0,他引:2
通过对比IPCC历次评估报告中全球碳循环的收支发现,尽管评估报告在估算各主要碳库及其间的通量时差别不大,但表层至中深层海水间溶解无机碳通量却存在巨大差异。利用δ13C的收支平衡检验了这一通量的适用范围,结果表明:IPCC 1996年和2007年评估报告对此通量估计过大,而1990年和2001年评估报告估计偏小。 相似文献
4.
Role of Acoustic Emission for Solving Rock Engineering Problems in Indonesian Underground Mining 总被引:2,自引:0,他引:2
Suseno Kramadibrata Ganda Marihot Simangunsong Kikuo Matsui Hideki Shimada 《Rock Mechanics and Rock Engineering》2011,44(3):281-289
In situ stress measurement is not well accepted yet in Indonesia due to the unavailability of technology, high costs and because
it is impractical in remote regions. Alternatively, the Kaiser effect of acoustic emission (AE) can be used as a method for
determining the stress-state at depth, without creating induced stress and is practical in remote areas. This paper is focused
on the development of the AE test. The research has started to study the phenomenon of stress memory in a rock sample, the
factors influencing the phenomenon, and finally, to determine the in situ stresses around underground excavations by applying
the AE method. It is expected that knowledge in gaining the most important input parameters for maintaining the stability
of underground excavations can be well understood and be reliably conducted at a reasonable cost. 相似文献
5.
Insaf S. Babiker Mohamed A. A. Mohamed Kaori Komaki Keiichi Ohta Kikuo Kato 《Journal of Oceanography》2004,60(3):553-562
Changes in patterns of undetectability and molar ratios of dissolved nutrients in the euphotic zone of the oligotrophic western
North Atlantic Ocean were investigated utilizing the Bermuda Atlantic Time-series Study (BATS) data set of the US Joint Global
Ocean Flux Study (JGOFS). Our aim was to examine the temporal dynamics of nutrient stocks over a decade (1989∼1998) and to
gain insight into the interactions between the different biotic and abiotic factors underlying BATS. Patterns of nutrient
undetectability clearly revealed the depleted nature of the nutrients in surface water at the BATS location, particularly
phosphorous. The N:P ratio was consistently far above the nominal Redfield ratio (mean, 38.5) but was significantly lower
during the 1993∼1994 period (22.1). Over the same period the proportion of samples depleted in N only increased while the
proportion of samples depleted in P only decreased. This indicates an overall reduction of N relative to P in the surface
water at BATS during the 1993∼1994 period, the reasons for this anomaly, though, are not clear. The correlation analysis between
the biotic and abiotic variables at BATS has indicated some interesting relationships that can help understand some of the
parameters affecting nutrient stocks in the euphotic zone and their consequent impacts on marine biota. Although nutrient
stocks in the oligotrophic environment are limited, they might be subject to interannual variation that may become anomalous
in some cases. These variations might underlay significant feedback mechanisms by affecting marine productivity, the prime
factor controlling the sequestration of atmospheric CO2 by the oceans.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
I.INTRODUCTIONAerosolcompositionisapieceofimportantinformationforradiationtransfer.Twoparameters,narnely,totalloadingandchemi... 相似文献
7.
A tephra layer offers an isochronous surface in sediments, thus serving as a key bed and/or an age marker. Recent high-resolution sediment research (e.g. varved sediments) has revealed optically invisible tephra fingerprints and provided high-precision tephra ages. However, a tephra-based correlation cannot succeed without detailed knowledge of the tephra characteristics in a proximal area to correlate with tephra in high-resolution sediments in remote areas. Here we documented the detailed characteristics of Towada-Chuseri (To-Cu) tephra, which is associated with the Middle Holocene volcanic explosivity index 5 eruption of Towada volcano, northeast Japan. We used To-Cu tephra samples to achieve the proximal–distal correlation of three members: Chuseri pumice (Cu), Kanegasawa pumice (Kn) and Utarube ash (Ut). These distal occurrences correlate with proximal To-Cu tephra based on volcanic glass morphology and refractive index, as well as on major element composition of volcanic glass shards. Refractive indices allow the preliminary correlation of each member, and major element composition helps in distinguishing Ut from the other members. Glass morphology provides additional support. These correlations reveal that To-Cu, especially Cu, covered central to northeast Japan while confirming that To-Cu is the representative tephra in the Middle Holocene of the Tohoku region. 相似文献
8.
Evolution and effect of the stress concentration and rock failure in the deep multi-seam coal mining 总被引:1,自引:0,他引:1
Mingwei Zhang Hideki Shimada Takashi Sasaoka Kikuo Matsui Linming Dou 《Environmental Earth Sciences》2014,72(3):629-643
Supports crushing accident occasionally occurs in the protected seam exploitation of deep multi-seam coal mining structure and results in adverse effect to the production. To prevent its recurrence in a newly developed working field, a 3D numerical extraction model was built based on the geologic and mining conditions of Jining coal mine to evolve the changes, state and characteristics of the reconstructed vertical and lateral stress in rock interlayer after protective seam exploitation. Stress release and increase zones of this mining structure were separated. Mining-induced localized stress concentration and the interlayer rock failure behavior were explored. The action of concentrated stress on the hydraulic supports in protected seam was discussed upon the major stress redistribution. Using the infinitesimal strain method, a mechanical model was created to further explore, from the vertical and lateral directions, the cause and mechanism of localized stress concentration and rock failure behavior in rock interlayer. The field investigation was finally performed to verify the numerical and mechanical results, and the essential control measures were proposed to prevent this accident. Key findings of this study bring some new insights into the deep multi-seam coal extraction and help to promote a more reliable underground mining. 相似文献
9.
Hideki Shimada Yanlong Chen Koichi Araki Takashi Sasaoka Kikuo Matsui 《Geotechnical and Geological Engineering》2012,30(2):289-297
Based on experimental and numerical investigations, the present paper focuses on under ground scope (UGS) chemical grouting
method that can actually improve the pipeline surrounding foundation to solve pipeline saggy damage. According to the experimental
results, a solution-type injection material could make lager soil deformation, using less total slurry amount than suspension-type
injection material. Therefore, a suspension-type injection material with shorter gel time is more suitable for the UGS method,
making it more effective to reinforce the pipeline foundation and restore pipelines. The results of some patterns of injection
tests revealed relationship between the behavior of the grouting material and the deformation of the soil. It is found that
the material can be injected into a foundation by fracture grouting if the permeation coefficient is lower than 1.00 × 10−3 mm/s. The situation was analyzed by using 2-D finite element method analysis software Phase2, and the analysis result proposes
that the real data and simulation data are nearly the same in impermeable soil. Furthermore, even if the construction object
is permeable soil, it can also be become impermeable soil by two phases grouting: soil improvement grouting and restoration
grouting. 相似文献
10.
In the Tokyo metropolis many geological surveys are carried out in conjunction with building construction work and urban base improvement undertakings. Furthermore, the Institute of Civil Engineering (ICE) of the Tokyo Metropolitan Government (TMG) has been conducting surveys on urban geology, land subsidence, and geodetics. Thus, ICE of TMG keeps a lot of geological data. In order to plan for a more effective use of these data, the Geotechnical Data Information System of Tokyo Metropolitan Government was organized in 1985, and since 1986, it has become fully implemented.This Geotechnical Data Information System has incorporated a relational data base into a mainframe computer, the NEC ACOS System 430, and as of March 1989 it can retrieve and graphically present borehole, deep-well, and groundwater data.The authors wish to introduce in this article the organizational structure of the Geotechnical Data Information System of TMG, a summary of the data base system, standards of input data, and applicable examples of the data base. 相似文献