Search

At present, there has been no mechanized equipment designed for the separation of the leaves from the stems of wakame in China, and the stem–leaf separation is mainly completed by manual work, which suffers from problems such as low efficiency, high cost, and poor quality. To develop mechanized stem–leaf separation equipment of wakame, it is necessary to have a preliminary understanding of the biomechanical characteristics of wakame. In this study, we adopted an electronic universal testing machine, a texture tester, and a friction tester to investigate the mechanical characteristics of the stems and leaves of salted wakame. Analysis was performed to clarify the effects of salted wakame thickness and loading speed on the tension, compression, shear, and separation mechanical properties as well as the effects of the loading speed, normal force, and contact material on the friction characteristics. As shown in the results, the average tensile strength, shear strength, and resilience of salted wakame stems were 2.27 MPa, 6.34 MPa and 0.27, respectively; the average tensile strength and shear strength of salted wakame leaves were 1.67 MPa and 2.93 MPa; the separation strength of the stems and leaves was 1.78 MPa, and the friction coefficient between salted wakame and stainless steel, silicone rubber, and vulcanized rubber was 0.38, 0.44 and 0.40 on average. In general, the increase in the loading rate, the shear strength, and the stem–leaf separation strength of salted wakame showed a downward trend, while the changes in the friction coefficient showed an upward trend, with no significant influence on the recovery and tensile strength. The tensile strength, resilience, shear strength, stem–leaf separation force, and strength increased as the thickness of the salted wakame improved. The friction coefficient of the salted wakame stems decreased with increasing the normal force, while the friction coefficient of the salted wakame leaves increased. In general, the increase in wakame thickness improved its mechanical properties, and the increase in the test loading rate led to the decrease in the mechanical properties of salted wakame. The research results in this paper can provide suggestions for the research and development of stem–leave separation equipment for saline salted wakame. [ABSTRACT FROM AUTHOR]

With the rapid development of transmission-line engineering in western China and the frequent occurrence of extreme natural disasters, a great deal of attention has been paid to the bearing capacity of foundation systems. The uplift capacity is still the controlling factor in the design, but neglecting the horizontal load component will induce great potential risks to the stability of the foundation. This paper describes the model test of rock-socketed piles (with soil overlying rock) that were subjected to axial and oblique tension impacts. Furthermore, the load displacement response, failure mode, and load transfer mechanism of the model piles were compared and discussed. The research indicates that the uplift capacity of the model pile under the oblique load can be remarkably reduced by up to 27.3% in comparison with the vertical uplift. Moreover, the load–displacement curve of the model pile under axial and oblique loads present abrupt failure. Notably, the failure mode under the axial tension is an inverted cone-shaped axisymmetric failure, and the failure mode under the oblique tension shows the wedge failure on the compression side and the interface separation on the tension side. The compression side and tension side show the opposite load transfer mechanism, thus inducing the presence of a bending moment in oblique tension pile. The position of the maximum bending moment occurs at the depth of 2.3–2.8d below ground surface. In summary, the research results of this paper have important guiding significance for design of transmission tower foundation in similar geological settings. [ABSTRACT FROM AUTHOR]

On August 27, 2014, a large-scale landslide occurred in Fuquan, Guizhou, China. This high-speed landslide caused considerable destruction; 23 people were killed, 22 were injured, and 77 houses were damaged. Field investigations, deformation monitoring, and numerical analyses have been performed to examine the characteristics and formation processes of this landslide. In the Xiaoba area, the slope showed a two-layered structure with a hard upper layer and a soft lower layer. Dolomite of the Dengying Formation in the slope front formed a locked segment controlling slope stability. Based on deformation and failure characteristics, the landslide is divided into sliding source area A and accumulation area B. The landslide is also divided into the following stages: bedding slip, tension cracking at the slope scarp, and the appearance of the locked section at the slope toe. Numerical calculations show that excavation led to maximum shear strain concentration along the interface of siltstone and slate in the middle of the slope, which became a potential sliding surface. Stress concentration and distribution of the plastic zone of the locked segment of the Dengying Formation dolomite occurred in the slope toe. Continuous rainfall caused the groundwater level to rise in the Xiaoba slope. The unfavorable geological structure was a determinant factor, and the combined effects of excavation and continuous rainfall were triggering factors that induced the landslide. The geomechanical mode for the Xiaoba landslide is sliding tension-shear failure. [ABSTRACT FROM AUTHOR]

This work is aimed at studying the mechanics characteristics of the self-anchored suspension bridge with extra-wide concrete girder during girder erection and system transformation. First, the determination and implementation processes of reasonable completion state were introduced briefly, taking the Hunan Road Bridge as the background project, which is the widest concrete self-anchored suspension bridge in China currently. Then, the ANSYS beam-type finite element model and field monitoring data were integrated to investigate the cable system evolutions during system transformation. Finally, the global refined finite element model was established using solid element to consider the shear lag effects in extra-wide girder. The measured data show that the cable displacements in tensioned domains were characterized by weak coherence and contraflexure characteristics. The longitudinal and transverse stresses of extra-wide girder distributed unevenly along transverse direction. The maximum shear lag coefficients of girder at completion state reached to 1.3. Moreover, small transverse compressive stress, or even the transverse tensile stress reaching to 1.80 MPa, appeared in the top plate segments. The measures including the arrangement optimization of transverse prestressed tendons and monitoring point redistribution were given. The research can provide references for the structural designing and safety control of the similar bridges. [ABSTRACT FROM AUTHOR]