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Soil Arch Evolution Characteristics and Parametric Analysis of Slope Anchored Anti-slide Pile
Sifeng Zhang,Chao Li,Hui Qi,Xingji Chen,Shuaishuai Ma 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11
The soil arching effect can significantly impact the bearing characteristics of the slope anchored anti-slide pile. Therefore, it is very important to investigate the internal force characteristics of the soil arch and the mechanism of pile-soil interaction. In this paper, the evolution mechanism and influencing parameters of the soil arching effect of anchored anti-slide pile are analyzed, from a qualitative and quantitative perspective through model tests and numerical simulation methods. Findings are summarized as follows: 1) the formation and evolution of the soil arches can be roughly divided into three stages: the initial stage, the development and formation of soil arches, and the failure and re-formation of soil arches. The stable arch feet are firstly formed, and a complete arch is generated. Then the landslide thrust is transmitted to form a stable anti-slide pile structure, so the anchored anti-slide pile can play a role in slope anti-slide. 2) During the formation and evolution of the soil arches, the soil particles between the piles transfer the landslide thrust to the anti-slide pile through the soil arches. 3) The bearing capacity of the soil arches decreases with the increase of the pile spacing. And the increase of the soil compaction can efficiently increase the bearing capacity of the soil arches and give full play to the role of slope anti-slide. 4) The growing of soil particle size, the enhancement of soil particle friction coefficient, and the decreasing of corresponding soil void ratio are all conducive to the formation of the soil arches. These can benefit the anti-sliding effect of the anchored anti-slide piles in engineering application.
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Low-Frequency Vibration Control of Metro Slab Track Based on Locally Resonant Theory
Chao Li,Sifeng Zhang,Qian Liu,Chong Zhou,Haichao Qin,Luyu Zhang,Minghu Zhai 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.6
Vibration control has always been one of the research hotspots in the field of urban metro system. Due to the unsatisfactory application effect of traditional vibration damping technology in practice, a novel method, based on the locally resonant theory, was introduced into metro vibration damping system to improve the low-frequency vibration reduction effect. Meanwhile, the new metro vibration reduction slab track was designed. Furthermore, the coupled model of the metro vehicle-slab track was established and verified, and the reduction effect of the new metro slab track on low-frequency vibration under the action of metro vehicles was analyzed. Results show that: 1) The new vibration reduction slab track is really in control of the low-frequency vibration (50 − 100 Hz), and the attenuation effect can reach 10 dB; 2) The new slab track has multiple low-frequency vibration band gaps, which can achieve multi-frequency vibration reduction; 3) The new slab track can reduce the vibration acceleration of the track, which can improve the comfort level of the vehicle. Therefore, the local resonance theory enriches the existing metro vibration reduction design theory and provides a method for the design of the metro vibration control.
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( Zhengyi Chai ),( Dexian Zhang ),( Sifeng Zhu ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.5
In this paper, the resource allocation problem with proportional fairness rate in cognitive OFDM-based wireless network is studied. It aims to maximize the total system throughput subject to constraints that include total transmit power for secondary users, maximum tolerable interferences of primary users, bit error rate, and proportional fairness rate among secondary users. It is a nonlinear optimization problem, for which obtaining the optimal solution is known to be NP-hard. An efficient bio-inspired suboptimal algorithm called immune clonal optimization is proposed to solve the resource allocation problem in two steps. That is, subcarriers are firstly allocated to secondary users assuming equal power assignment and then the power allocation is performed with an improved immune clonal algorithm. Suitable immune operators such as matrix encoding and adaptive mutation are designed for resource allocation problem. Simulation results show that the proposed algorithm achieves near-optimal throughput and more satisfying proportional fairness rate among secondary users with lower computational complexity.
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Huili Wang,Shaobo Zhou,Yan Zhang,Sifeng Qin 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.6
Tensile-plate anchorage (TPA) is widely used in steel cable-stayed bridges. However, due to the complex geometry of the anchorage, the stress concentration area will appear under the action of the dynamic load, leading to fatigue failure. In this paper, taking a cable-stayed bridge as an example, the theoretical analysis and experimental investigation of the fatigue performance of TPA are performed. At first, a full-bridge finite element model was set up to obtain the severest cable force and cable force amplitude under fatigue load. Then the fatigue test of 1:1.5 specimen was carried out. The maximum principal stress of TPA was 32.24 MPa and the maximum deformation was 1.6 mm. During the loading process, TPA was in elastic working state. After 2 million fatigue load cycles, no cracks were found. At last, the fatigue performance of TPA was analyzed with the theory of critical distances (TCD). The results of the theoretical analysis and fatigue test show that the fatigue performance of TPA could satisfy the use requirement.
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Lingxin Li,Han Li,Yanju Long,Shan Wang,Yu Chen,Sifeng Zhang,Lulu Wang,Lijun Luo,Fengzhi Jiang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.1
In the present work, a direct Z-scheme AgI/BiOBr heterojunction displaying improved photocatalytic activity was designed by a chemical bath deposition method. The obtained photocatalysts were systematically characterized through XRD, SEM, XPS, BET and UV-Vis diffuse reflectance spectroscopy. The synthesized AgI/BiOBr photocatalyst displayed superior photocatalytic performance in the case of 17α-ethinylestradiol (EE2), where 97.0% compound has been removed within 9 min of irradiation. The rate constant using AgI/BiOBr photo-catalyst was 16.0 and 138.7 times more than that of pure AgI and BiOBr, respectively. Furthermore, the photocatalytic mechanism was investigated. The results of this study indicated that AgI/BiOBr was a stable and efficient photocatalyst, with promising practical applications.
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