Tianjin Institute of Geotechnical Investigation and Surveying

Hongqi, China

Tianjin Institute of Geotechnical Investigation and Surveying

Hongqi, China

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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) | Year: 2010

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.


Liu M.,China University of Geosciences | Liu X.,China University of Geosciences | Ma A.,Tianjin Institute of Geotechnical Investigation and Surveying | Li T.,Shanghai JiaoTong University | Du Z.,China University of Geosciences
Continental Shelf Research | Year: 2014

Detecting a regular pattern of chlorophyll-a (Chl-a) in the ocean can provide a preliminary scientific understanding of regional environmental changes. The objective of this research was to identify the potential of a wavelet transform to capture and describe both the stationary level and anomalous variability of Chl-a. An 11-year time series (from July 2002 to December 2012) of the Moderate Resolution Imaging Spectroradiometer (MODIS) chlorophyll-a product in the Northern South China Sea (NSCS) was collected. The Data INterpolating Empirical Orthogonal Functions (DINEOF) was used to reconstruct the original MODIS data. The approximation and detailed components from the original series of the MODIS Chl-a data were considered to be a source of the stationary level and anomalous variability of Chl-a, respectively. The stationary level of the Chl-a concentration was characterized by the Chl-a concentration of the coastal areas that was higher than that of the open ocean area, as well as monthly, seasonal and annual averaged Chl-a concentrations concentrating on between 0.05 and 0.25mgm-3. The anomalous variability of Chl-a has a short-oscillating period of 0.5 years; specifically, the Chl-a negative amplitude occurred in spring and autumn, and the positive amplitude was recorded in winter and summer. Furthermore, a long-oscillating period of four years, that is, the inter-annual singularity of Chl-a, primarily appeared in May 2003, May 2007 and May 2011. The maxima of the Chl-a concentration were dominated by between 0.5 and 1mgm-3. The peak winter Chl-a concentration was mainly located in the open ocean area, and the peak summer Chl-a concentration was mostly limited to the coastal region. This study suggests that a wavelet transform is promising for detecting the anomalous and stationary variability of ocean parameters. © 2014 Elsevier Ltd.


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) | Year: 2010

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.


Chen L.,Tianjin Research Institute of Water Transport Engineering of Ministry of Transport | Zhang F.,Hohai University | Li Z.,Tianjin Research Institute of Water Transport Engineering of Ministry of Transport | Li Y.,Tianjin Institute of Geotechnical Investigation and Surveying | Huang S.,Tianjin Research Institute of Water Transport Engineering of Ministry of Transport
Journal of Hohai University | Year: 2016

The location of vacuum sources with negative pressures was considered in analysis of the effects of dredger fill foundation reinforcement under vacuum preloading. Model tests were performed to simulate dredger fill foundation reinforcement using the vacuum preloading method, with vacuum sources located at the top and bottom. Over the course of foundation consolidation, the amounts of water drainage and settlement for different soil layers and the vacuum degree at different depths were monitored, and the transmission efficiency of the vacuum degree and consolidation settlement properties for soil layers with vacuum sources located at different depths were studied. Results show that the vacuum preloading method, with vacuum sources located at the bottom of the dredger fill foundation, can enhance the transmission efficiency of the vacuum degree, shorten the drainage path in deep soil layers, change the seepage direction in middle soil layers, and maintain a high vacuum degree in upper soil layers. Meanwhile, deep soil layers can be reinforced effectively, and the consolidation settlement tends to be more uniform. Moreover, this method can increase the effective reinforcement depth to a great extent and reduce the post-construction settlement to a certain degree. © 2016, Editorial Office of Journal of Hohai University (Nature Sciences). All right reserved.


Song J.,Jilin University | Wang Q.,Jilin University | Sun T.,Tianjin Institute of Geotechnical Investigation and Surveying | Li X.-R.,Tianjin Investigation and Research Institute | And 2 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2010

The drain pipes, which were applied to treat the dredger fill by vacuum preloading, were always plugged by fine particles. It is essential to keep out of construction period for delay to improve the efficiency of the dredger fill consolidation. The test of dead-weight sludging drainage plus a combination of vacuum method of drainage in the laboratory was carried out. As vertical drainage channels, the drain pipes were experimentally used during the first-stage called dead-weight sludging drainage. Then the drain pipes were filled with medium-coarse sand to consolidate the dredger fill by vacuum method. The pore water pressure of varied depths and ranges were continuously observed especially to approach the primary-stage consolidation law. On account for the balance equation of water in the soil seepage, the major changes of pore water pressure were dominated. The mechanism of the pore water pressure changes during the first stage was explained accordingly. In order to fine consolidation the equivalence circle diametric was determined by sand drain theory and the pore water pressure curves. So drainpipe spacing to achieve the same desired effect of consolidation was determined under different circumstances whether the soil is near or far from the drain for the actual project design parameters.


Yan Z.,Wuhan University | Ding L.,Tianjin Institute of Geotechnical Investigation and Surveying | Ding L.,Wuhan University | Huang E.,Tianjin Institute of Geotechnical Investigation and Surveying | Yu X.,Wuhan University
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2013

We propose a new method for ambiguity fixing between network RTK reference stations, which can improve the ratio value and success rate for the ambiguity test when ambiguity fixed needs long time passing the ratio test. Firstly, wide-lane and L2 ambiguity, with its variance-covariance matrix are formed from the original ambiguity by integer transformation. Secondly, LAMBDA method is used to sequentially fix the transformed block ambiguity. The results show that the new method not only can fast and reliably fix the wide-lane ambiguity, but also improve the ratio value and success rate when ambiguity fixed correctly, which reduce the initialization time of ambiguity fixing.


Zhang X.,Wuhan University | Ding L.,Wuhan University | Ding L.,Tianjin Institute of Geotechnical Investigation and Surveying
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2013

This paper analyzes the Compass observations through the zero baseline experiments, including the time series of signal to noise ratio (SNR), multipath and the Compass single-difference residuals, which change with the elevation angles. Compared with GPS observations, the Compass signals have some differences. For example, GPS L1 signal is stronger than L2 signal, while the Compass B2 signal is stronger than B1. The Compass carrier phase single-difference residuals changes with the elevation can be used to refinement the elevation-weighting method and SNR-weighting method. The experimental results show that the accuracy of Compass observations are reliable, which can be used in high-precision navigation and positioning, meanwhile, the quality analysis of the Compass observations can provide the basis for building stochastic model.


Feng S.L.,Tianjin University | Guo Q.Q.,Tianjin University | Wu Y.H.,Tianjin Institute of Geotechnical Investigation and Surveying
Applied Mechanics and Materials | Year: 2014

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.


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 | Year: 2014

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.


Jia Z.,Tianjin Institute of Geotechnical Investigation and Surveying
Journal of Geomatics | Year: 2011

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.

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