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Xu S.,Xian University of Architecture and Technology | Kong Z.,Anhui University of Technology | Zhangs C.,Zhejiang Construction Investment Group Co.
Advanced Materials Research

The characterstics of corrosion is important to asseess structure safety, however, because of the complexity of corrosion, it is hard to see papers anout it. In order to study the characterstics of corrosion specimen surface, two methods are used to obtain corrosion specimens, one method is constant temperature and humidity, the other is natural corrosion. Then roughness tester is used to detect the profile of corrosion specimen surface, and the surface characterization is analyzed by fractal theory. Through the experimnet, we find the law of power relationship between fractal dimension and the depth of localized corrosion, so it will help to solve the difficulty of safety assessment for in-service steel structure. © (2011) Trans Tech Publications, Switzerland. Source

Yu J.,Zhejiang Construction Investment Group Co. | Yu J.,Zhejiang University of Technology | Liu S.,Nanjing Southeast University
Geotechnical Special Publication

In order to guarantee tunnel construction safe, the stability of the front slope at the entrance of tunnel was improved by cutting slope with anchor, jet concrete and steel net. At first, the geological condition of front slope at the entrance of the tunnel was investigated. Then, the mechanism of cutting slope to improve the stability of front slope was analyzed. At last, the angle and configure of cutting slope with alluviation residual soil was simulated. The result was shown that when front slope angle was more than thirty degrees, it was obvious and feasible to improve its stability through cutting slope. When its angle was less than thirty degrees, cutting slope was not feasible. It was result that the safety factor of front slope was more than one point six and it was safe enough to meet the need of tunnel excavation. © 2011 ASCE. Source

Yu J.,Zhejiang University of Technology | Yu J.,Zhejiang Construction Investment Group Co. | Yu J.,Zhejiang University | Lu J.,Zhejiang Construction Investment Group Co. | Gong X.-N.,Zhejiang University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering

The reason of earth pressure alteration is analyzed, and the formula for calculating the earth pressure considering the displacement of structures of asymmetric excavations are put forward. The earth pressure is calculated, compared and analyzed according to the monitoring data. They are almost equal. At the same time, the earth pressure of asymmetric excavations is the comprehensive result of soil displacement around them. The soil displacement is almost equal to the deformation of structure and earth pressure is less than the internal force of supporting structures. A formula for earth pressure considering water pressure and asymmetric displacement is concluded. It is concluded that the earth pressure for dewatering gets less and it benefits to the stability of excavations, and vice versa during raining. The earth pressure is nearly equal to the force of lining. It may be useful for the design of similar projects. Source

Lu J.,Zhejiang Construction Investment Group Co. | Yu J.,Zhejiang University of Technology | Chen J.,Zhejiang Construction Investment Group Co. | Ye Q.,Zhejiang Construction Investment Group Co. | Zhao C.,Tongji University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

Model test is a necessary scientific method which is used in the research on bearing performance of pile foundation. The differences of bearing capability of piles using different piling techniques are significantly studied through designing model test and analyzing test data, and the influence of unloading effect caused by cavities drilling to bearing mechanism of bored piles, as well as the mechanical and settlement property of piles, are also discussed by comparative analysis. The study indicates that: Q-S curves of test piles appear steep drop type; the bearing capacity of jacked pile is the most prominent of all, but less obvious in pre-buried pile and bored piles in steep performance. The load transfer performance of test piles will be affected by different construction methods, and the load transfer capability of jacked pile in the depth direction is worse than that of pre-buried pile and bored piles due to the difference between compacting effect and unloading effect. The skin frictions of four piles are intensified in certain depth, and the strengthened position of jacked pile is slightly higher than that of bored piles and pre-buried pile, which is caused by the fact that compacting effect makes skin friction increase. Otherwise, unloading effect caused by cavities drilling of bored piles and the backout of film wrapped around pre-buried pile weakens skin friction to a certain extent. The extremum exertion and extreme points location of skin friction of piles are highly influenced by different piling techniques. Skin friction and tip resistance do not display in identical time and do not achieve maximum at the same time; and the proportion of tip resistance in total working load varies with upper load. Source

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