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Feng S.L.,Tianjin University | Guo Q.Q.,Tianjin University | Wu Y.H.,Tianjin Institute of Geotechnical Investigation and Surveying
Applied Mechanics and Materials

Temporary bracing is often viewed as an unnecessary step in the process of constructing a structural facility. Unfortunately, many times this often-neglected step becomes the subject of avoidable litigation and lawsuits. This paper presents a remedy case of a deep foundation pit during the construction of the bracing system located at the business center in HePing district, TianJin. Through frequent inspection and suitable countermeasures, the potential disaster was mitigated in time. There were some lessons learned from this case history. © (2014) Trans Tech Publications, Switzerland. Source

Liu R.,State Key Laboratory of Hydraulic Engineering Simulation and Safety | Wang L.,State Key Laboratory of Hydraulic Engineering Simulation and Safety | Wang L.,Tianjin Institute of Geotechnical Investigation and Surveying | Ding H.-Y.,State Key Laboratory of Hydraulic Engineering Simulation and Safety | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering

As a towering building, the offshore wind turbine is often subjected to significant horizontal load. The large-diameter shallow bucket foundation is a new kind of foundation to adapt to the special load conditions of offshore in China. The classical approach for the bearing capacity is not able to evaluate the bearing capacity of large-diameter bucket foundation. The failure envelopes of large-diameter bucket foundation on soft soil ground without drainage conditions in V-H, V-M, H-M and V-H-M loading spaces are investigated by means of the finite element method. Some formulas are obtained to describe the failure envelopes in V-H and V-M loading spaces. It is shown that the failure envelopes in V-H and V-M spaces are symmetric, while the failure envelope in H-M space becomes more asymmetric with the increasing depth ratio. The vertical load V affects the shape of the failure envelope in V-H-M loading space. The asymmetry of the failure envelope around M-axial recedes with the increasing vertical load. According to the relationship between the actual combined loading and the computed failure envelopes, the stability of large-diameter shallow bucket foundation can be determined. Source

Jia Z.,Tianjin Institute of Geotechnical Investigation and Surveying
Journal of Geomatics

The method of the subway shield gateway steel ring considered to a circle of the solid space is applied. The process of measuring and calculating the center coordinate and the radius of the steel ring circle is analyzed. The center coordinate of the steel ring circle can be measured accurately. Source

Song J.,Jilin University | Wang Q.,Jilin University | Chen H.-E.,Jilin University | Sun T.,Tianjin Institute of Geotechnical Investigation and Surveying | And 2 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition)

The dredger fill foundation is popularly treated by vacuum preloading. But the drain pipes are always clogged by fine particles which cause the construction to be delayed. In order to improve the efficiency of the dredger fill consolidation, a laboratory test was designed to study consolidation law under the comditions of gravitational drainage clogged combined with vacuum preloading method for heavy clay and saliniferous dreder fill. Engineering geology characteristics of heavy clay and saliniferous dredger fill was analyzed. And the small cubic crystals overlapped on the surface of the particles were identified by soluble salts test and X-ray diffraction approach. When the microstructure was studied by scanning electronic microscope(SEM) during the process of consolidation, it was indicated that with the decreased of moisture content in heavy clay and saliniferous dredger fill, the number of halite was running off by water drainage in the process of gravitational drainage stage. So the seepage channels became instability due to the unstable microstructure. Furthermore, particle fractal dimension was taken as the microstructure index to determine the characteristics of the heavy clay and saliniferous dredger fill on the process of consolidation. The results showed that particle fractal dimension was increased by consolidation as the result of the reduction of the number of cubic crystals flowed off by water drainage. Source

Zhang Z.-Q.,Jilin University | Zhang Z.-Q.,Chinese Academy of Sciences | Wang Q.,Jilin University | Qin Y.,Jilin University | And 3 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition)

Hydraulic fill had become one of main method to make up for the deficiency of construction land in the coastal regions. In order to obtained the better consolidation effect of dredger fill in a relatively short period of time, considering dredger fill's special engineering geological nature and periodic strength growth in the strengthening process, the idea about reinforcement at the same time of blowing has been proposed. Indoor simulation experiment carried out under the guidance of the idea. Test results showed that different stages of dredger fill reinforcement strength showed growth zoning. Soil strength increased rapidly when the distance between the soil and vertical drain body was less than 25 cm. With the reinforcement of time extension the strength of reinforced soil increased in the overall. When the vacuum load lasted one month, some of reinforced soil's bearing capacity had been reached 80 kPa. Strength of growth was closely related to the size of the external load, the length of the infiltration path, size of additional stress. Step-by-step reinforcement method inhibited the formation of clay ring to some extent, Shorten the vacuum loading time and save time. Step-by-step reinforcement method is advantageous for dredger fill's consolidation a reinforced fill. Source

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