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Li D.-P.,PLA University of Science and Technology | Zhang W.-F.,PLA University of Science and Technology | Zhang W.-F.,The Third Research Institute of Engineering Corps | Zhao J.-K.,PLA University of Science and Technology | Sun Y.-H.,PLA University of Science and Technology
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

Aiming at simplifying the application of the Culmann's graphical construction in fold line slopes, the bio-fold and tri-fold line slopes behind the retaining wall are taken as the analytical models based on Wang Kuihua's amelioration on straight line slopes. According to the Coulomb's earth pressure theory and the similarity between the geometric triangle and the force vector triangle, a new graphical method is developed. Compared with the Culmann's graphical construction, the newly ameliorated approach needn't calculate the weight of the slide masses, and either needn't measure the line segments out proportionally to present the weight of the slide masses. The proposed approach needs fewer calculations and is more convenient, and the results are more precise. Source


Rui R.,Wuhan University of Technology | Xia Y.-Y.,Wuhan University of Technology | Gu J.-C.,Wuhan University of Technology | Gu J.-C.,The Third Research Institute of Engineering Corps | Chen Z.-S.,Guangdong Road and Bridge Construction Development Co
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

The bond stress between grout body and surrounding rock is the key problem in the load transfer mechanism of pressure-dispersion anchors. At present, it is also difficult to get the bond stress directly. It is mostly obtained by subtracting pressure stress values along the axes, which are calculated by axial pressure strain value from strain gages. By this method, the error is large because the pressure stain is not uniform in the section and the radial strain is not taken into account. Due to the axially symmetric stress condition of the grout body of anchorage section, self-made strain bricks are fixed into the right places of the grout body. The bricks are used to measure the shear stain near wall of the hole so as to reflect the characteristics of the bond stress on the interface. The grip between gout and steel strand is also tested by use of another 5 m-long cable for calculating prestress loss. The influences of axial compression and radial swelling are analyzed, and the distribution rules of axial strain, radial strain and tangential shear stress are discussed. FLAC3D is used to simulate pressure-dispersion anchors in the field test. The uniformity of axial stress in grout section, and the relationship and differences between tangential shear stress and bond stress of grout body are discussed. Finally, the distribution characters of axial stain and shearing stress are achieved. The effective length of anchorage section is confirmed to be 2 m, and the design length of anchoring section with change from 5 m to 3 m is put forward. Source


Rui R.,Wuhan University of Technology | Xia Y.-Y.,Wuhan University of Technology | Gu J.-C.,Wuhan University of Technology | Gu J.-C.,The Third Research Institute of Engineering Corps | Chen C.,China Petrochemical Sales Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

The existing studies indicate that the shear stress between grout body and rock mass along the anchoring segment of a prestressed anchor is not uniform. The non-uniform shear stress design method is one of the development trends for prestressed anchor design, but the current design methods still treat the shear stress as uniform one. The reason lies in that widely recognized shear stress distribution pattern and formula have not been established. However, the bearing capacity of pressure-dispersive anchors is much higher than that of the tension ones, which means that the shear stress between grout body and rock mass in anchoring segment is more concentrated. So the non-uniform shear stress design method is more necessary to pressure-dispersive anchor. Three indoor full size simulating experiments are undertaken to get the shear stress, and multi-factor numerical simulations are done to discover distribution characters of the shear stress. Two distribution patterns are drawn from the indoor tests and calculations, and key parameters of the shear stress distribution curves are confirmed through the numerical calculations. Equation derivations are done based on the two distribution patterns, and a non-uniform shear stress design method of pressure-dispersive anchor is finally established. It is proved that the proposed method agrees with the indoor experiments and numerical simulations. Source


Cheng Y.-H.,PLA University of Science and Technology | Wang M.-Y.,PLA University of Science and Technology | Wang M.-Y.,Nanjing University of Science and Technology | Shi C.-C.,PLA University of Science and Technology | And 3 more authors.
Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2015

Impact experimental results for concrete targets and the factors influencing target behaviors in four velocity ranges were presented in order to evaluate the impact resistance of concrete. Two types of velocity partition means were concluded and four velocity ranges were suggested based on material dynamic responses and apparent penetration behaviors. The experimental studies were reviewed from low velocity to hypervelocity. In low velocity range(impact velocity within 40 m/s), failure modes of beams, columns, slabs and shells were briefly summarized. In medium velocity range(impact velocity between 40 m/s and 1 km/s), the effects of relative diameter of missile to target, coarse aggregate, uniaxial compressive strength and steel bar on the thick target penetration were discussed. In high velocity range(impact velocity between 1 km/s and 2 km/s), the semi-hydrodynamic transition velocity and cratering effects were introduced. In hypervelocity range (impact velocity over 2 km/s), the density-dominant hydrodynamic penetration phenomena were described. Some research proposals on concrete penetration were given for the further study. ©, 2015, Zhejiang University. All right reserved. Source

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