Construction and Testing of Deep Foundation Improvement Using the Deep Cement Mixing Method

2009 ◽  
pp. 224-224-10 ◽  
Author(s):  
R Babasaki ◽  
K Suzuki ◽  
S Saitoh ◽  
Y Suzuki ◽  
K Tokitoh
Keyword(s):  
Deep Foundation ◽  
Mixing Method

scholarly journals Calculation Model for the Mixing Amount of Internal Curing Materials in High-strength Concrete based on Modified MULTIMOORA

2020 ◽  
Vol 27 (1) ◽  
pp. 455-463
Author(s):  
Lixia Guo ◽  
Minghua Wang ◽  
Ling Zhong ◽  
Yanan Zhang
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Calculation Model ◽  
Internal Curing ◽  
Total Water ◽  
Water Release ◽  
Strength Concrete ◽  
Numerical Example ◽  
Comprehensive Performance ◽  
Mixing Method

AbstractThe internal curing technology has been widely applied to high-strength concrete, for it can make the high-strength concrete marked by low shrinkage and durable frost resistance. The key to its extension and application lies in the reasonable mixing amount of internal curing materials. To address this problem, scholars have proposed a method for determining the water demand in internal curing; however, the water release of internal curing materials is difficult to obtain by measurement due to the mixing method. Therefore, this paper proposed a calculation model for the mixing amount of internal curing materials based on the modified MULTIMOORA method (Multi-Objective Optimization on the basis of Ratio Analysis plus full multiplicative form). First, different internal curing materials (super absorbent polymer (SAP), lightweight aggregate (LWA)) and pretreatment methods were selected to calculate their compressive strength, self-shrinkage and frost durability according to a proposed test scheme on the mixing amount of internal curing materials, and in such case, the comprehensive performance evaluation of the above indexes was turned into a multi-attribute decision-making problem. Second, the ordered weighted averaging (OWA) method and the entropy weight method were used to determine the subjective and objective weights of the indexes respectively, to eliminate the impact of outliers in the subjective evaluation values. Finally, the comprehensive performance of each test group was sorted using MULTIMOORA, and based on the sorting results and the calculation model, the mixing amount of internal curing materials was determined. The numerical example application results showed that the mixing amount of SAP curing material calculated based on the model herein was 1.276 kg/m3, and the mixing method adopted the pre-water absorption method with the total water-binder ratio unchanged. The numerical example evaluation results were in good agreement with the test results. The internal curing effect of SAP was better than that of LWA, and reached the best when the mixing amount was calculated at 25 times the water release rate and the requirement for the maximum total water diversion was met. The study may provide new ideas for extension and application of the internal curing technology.

scholarly journals Visual evaluation of relative deep mixing method type of ground-improvement method

2021 ◽  
pp. 100233
Author(s):  
Koki Nakao ◽  
Shinya Inazumi ◽  
Toshiaki Takaue ◽  
Shigeaki Tanaka ◽  
Takayuki Shinoi
Keyword(s):  
Ground Improvement ◽  
Visual Evaluation ◽  
Deep Mixing ◽  
Improvement Method ◽  
Mixing Method

scholarly journals Comparative Study of the Field Performances of Pressure-Grouted Micropiles Using Gravity and Packers

2021 ◽  
Vol 11 (15) ◽  
pp. 6736
Author(s):  
Ong Heo ◽  
Yeowon Yoon ◽  
Jinung Do
Keyword(s):  
Urban Areas ◽  
High Performance ◽  
Driving Forces ◽  
Field Performance ◽  
Underground Space ◽  
Creep Tests ◽  
Deep Foundation ◽  
Installation Depth ◽  
Pressure Grouting ◽  
The One

When underground space requires excavation in areas below the water table, the foundation system suffers from buoyancy, which leads to the uplifting of the superstructure. A deep foundation system can be used; however, in cases where a hard layer is encountered, high driving forces and corresponding noises cause civil complaints in urban areas. Micropiles can be an effective alternative option, due to their high performance despite a short installation depth. Pressurized grouting is used with a packer to induce higher interfacial properties between micropile and soil. In this study, the field performance of micropiles installed using gravitational grouting or pressure-grouted using either a geotextile packer or rubber packer was comparatively evaluated by tension and creep tests. Micropiles were installed using pressure grouting in weak and fractured zones. As results, the pressure-grouted micropiles showed more stable and stronger behaviors than ones installed using the gravitational grouting. Moreover, the pressure-grouted micropile installed using the rubber packer showed better performance than the one using the geotextile packer.

scholarly journals Surface modification of YS-20 with polydopamine for improving the tribological properties of polyimide composites

Friction ◽  
2021 ◽  
Author(s):  
Liangfei Wu ◽  
Zhaozhu Zhang ◽  
Mingming Yang ◽  
Junya Yuan ◽  
Peilong Li ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Tribological Properties ◽  
Metallic Copper ◽  
Great Effort ◽  
Modified Polymer ◽  
Milling Method ◽  
Multi Walled Carbon Nanotubes ◽  
Mixing Method ◽  
Walled Carbon Nanotubes ◽  
Polymer Powders

AbstractRecently, great effort has been devoted to prepare various reinforce fillers to improve polymer performances, but ignoring the importance of raw polymer powders which are indispensable parts of hot-pressed polymer composites. Herein, we engineer raw polyimide (PI) powders with the assistance of polydopamine (PDA) in aqueous solutions. After the modification, polymer powders change from hydrophobic to hydrophilic, which makes it is possible to further modification of polymer powders in liquid phase. During the curing process of modified polymer powders, the partial dehydration of the catechol groups and crosslinking of PDA via C-O-C bonds are confirmed. Based on the features of PDA, a non-destructive mixing method is utilized to realize homogeneous dispersion of multi-walled carbon nanotubes (MWCNTs) in polymer matrix. In comparison with ball milling method, this way can preserve the integrated innate structure of MWCNTs effectively. Besides, by taking full advantage of the reducing and metal-coordination capability of PDA, Cu2+ is successfully loaded onto the surfaces of polymer powders. The related characterizations demonstrate that Cu2+in situ converts to metallic copper rather than copper oxide during the hot pressing process. The tribological properties of corresponding polymer composites are also studied. These results indicate that modifying polymer powders with PDA is multi-profit and presents practical application prospect.

scholarly journals Analysis of Seepage Characteristics of a Foundation Pit with Horizontal Waterproof Curtain in Highly Permeable Strata

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1303
Author(s):  
Chenghua Shi ◽  
Xiaohe Sun ◽  
Shengli Liu ◽  
Chengyong Cao ◽  
Linghui Liu ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Theoretical Calculation ◽  
Calculation Method ◽  
Design Method ◽  
Water Pressure ◽  
Water Inflow ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Seepage Characteristics

At present, jet-grouted horizontal waterproof curtain reinforcement has become an essential method for deep foundation pit groundwater control. However, there is still a lack of an effective theoretical calculation method for horizontal waterproof curtain reinforcement, and there is little research on the seepage laws of foundation pits under different horizontal waterproof curtain conditions. Based on Darcy’s seepage theory, theoretical analysis models of deep foundation pit seepage were established considering the effect of a horizontal curtain in a highly permeable formation. Through the established models, the calculation method of the water inflow and the water pressure under the condition of a horizontal curtain was derived. Then through indoor tests, the reliability of the theoretical calculation method was verified. Furthermore, the established theoretical calculation method is used to analyze the influence of various factors on the water inflow and the water pressure, such as the ratio of hydraulic conductivity of the horizontal curtain to surrounding soil, thickness, and reinforcement position of the horizontal curtain. It is found that the hydraulic conductivity ratio has the most significant influence on the seepage characteristics of the foundation pit. Finally, the design method was applied to an example of the horizontal waterproof curtain of the foundation pit, which is located at Juyuanzhou Station in Fuzhou (China). The water inflow per unit area is 0.36 m3/d in the foundation pit, and this implies that the design method of the horizontal waterproof curtain applied for the excavation case is good and meets the requirements of design and safety.

A Fe3+-crosslinked pyrogallol-tethered gelatin adhesive hydrogel with antibacterial activity for wound healing

2020 ◽  
Vol 8 (11) ◽  
pp. 3164-3172 ◽  
Author(s):  
Ning Han ◽  
Ziyang Xu ◽  
Chunyan Cui ◽  
Yuan Li ◽  
Dongfei Zhang ◽  
...  
Keyword(s):  
Wound Healing ◽  
Antibacterial Activity ◽  
Strong Adhesion ◽  
Mixing Method ◽  
Antibacterial Capacity

A tunicate-inspired gelatin-based hydrogel prepared by a simple mixing method, exhibits strong adhesion and antibacterial capacity, and facilitates wound healing.

Mechanical Analysis of Enclosure Pile under Different Constraints

2011 ◽  
Vol 90-93 ◽  
pp. 485-489
Author(s):  
Li Guo ◽  
Peng Li He ◽  
Guang Jun Zhang
Keyword(s):  
Mechanical Analysis ◽  
Subway Station ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Retaining Structure ◽  
Cantilever Structure ◽  
Reinforcement Measures

The enclosure pile is extensively used as retaining structure in the foundation pit excavation. And it is always combined with other reinforcement measures. So it is unreasonable to a certain degree that the enclosure pile is analyzed as cantilever structure. Taken the deep foundation pit of a subway station in Hefei for instance, the effect of other reinforcement measures on restrained conditions of enclosure piles in the paper was taken into account. And the behavior of enclosure pile under various restrained conditions was analyzed. Based on that, some helpful suggestions for practical retaining structure of foundation pit were put forward.

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