A Case Study of the Rapid and Long Runout Landslide at Hong′ao Waste Disposal Site in Shenzhen, China

Kai Wang,Shaojie Zhang,Fangqiang Wei,Hongjuan Yang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.3

A disastrous landslide occurred at the Hong’ao Waste Disposal Site in Shenzhen, China on December 20, 2015, involving a volume of 2.7 × 106 m3 of municipal solid waste (MSW) that travelled a distance of 700 to 800 m, covering an area of 3.8 × 105 m2 and caused 90 casualties. The geomorphological and geological characteristics of the waste disposal site were carefully examined and the landslide was classified as an extremely rapid flowslide. The major feature of the waste site was the basin-like structure with the bottom composed of low-permeable granite bedrock. Therefore, surface runoff could easily accumulate in the MSW due to the lack of drainage system, resulting in an increasing groundwater level. Laboratory tests, including physical characterization, Consolidation Isotropic Undrained (CIU) test and direct shear test were conducted to characterize the material properties of the MSW. Physical characterization indicated the MSW belongs to sandy silt, CIU tests indicated that static liquefaction was conducive to high-speed sliding. The direct shear test data were used to carry out numerical analysis of slope stability, in which the continuous rise in the groundwater level was taken into account. Numerical simulation showed that the pore water pressure induced by underground water seepage and gradual loading from the upper MSW placement aggravate the failure. Consequently, the main reason of the landslide could be concluded as follows: 1) the perched groundwater level due to a large upstream catchment area and the lack of drainage system; 2) the excess pore water pressure induced by static liquefaction played a significant role in its mobility.

Investigation lateral deformation and failure characteristics of strip coal pillar in deep mining

Chen, Shaojie,Qu, Xiao,Yin, Dawei,Liu, Xingquan,Ma, Hongfa,Wang, Huaiyuan Techno-Press 2018 Geomechanics & engineering Vol.14 No.5

In deep mining, the lateral deformation of strip coal pillar appears to be a new characteristic. In order to study the lateral deformation of coal-mass, a monitoring method and monitoring instrument were designed to investigate the lateral deformation of strip coal pillar in Tangkou Coalmine with the mining depth of over 1000 m. Because of without influence of repeated mining, the bedding sandstone roof is easy to break and the angle between maximum horizontal stress and the roadway is small, the maximum lateral deformation is only about 287 mm lower than the other pillars in the same coalmine. In deep mining, the energy accumulation and release cause a discontinuous damage in the heterogeneous coal-mass, and the lateral deformation of coal pillar shows discontinuity, step and mutation characters. These coal-masses not only show a higher plasticity but also the high brittleness at the same time, and its burst tendency is more obvious. According to the monitoring results and theoretical calculations, the yield zone of the coal pillar width is determined as 15.6 m. The monitoring results presented through this study are of great significance to the stability analysis and design of coal pillar.

Phase Transitions of Formamidinium Lead Iodide Perovskite under Pressure

Jiang, Shaojie,Luan, Yiliang,Jang, Joon I.,Baikie, Tom,Huang, Xin,Li, Ruipeng,Saouma, Felix O.,Wang, Zhongwu,White, Timothy J.,Fang, Jiye American Chemical Society 2018 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.140 No.42

<P>The pressure-induced structural evolution of formamidinium-based perovskite FAPbI<SUB>3</SUB> was investigated using <I>in situ</I> synchrotron X-ray diffraction and laser-excited photoluminescence methods. Cubic α-FAPbI<SUB>3</SUB> (<I>Pm</I>3̅<I>m</I>) partially and irreversibly transformed to hexagonal δ-FAPbI<SUB>3</SUB> (<I>P</I>6<SUB>3</SUB><I>mc</I>) at a pressure less than 0.1 GPa. Structural transitions of α-FAPbI<SUB>3</SUB> followed the sequence of <I>Pm</I>3̅<I>m</I> → <I>P</I>4/<I>mbm</I> → <I>Im</I>3̅ → partial amorphous during compression to 6.59 GPa, whereas the δ-phase converted to an orthorhombic <I>Cmc</I>2<SUB>1</SUB> structure between 1.26 and 1.73 GPa. During decompression, FAPbI<SUB>3</SUB> recovered the <I>P</I>6<SUB>3</SUB><I>mc</I> structure of the δ-phase as a minor component (∼18 wt %) from 2.41-1.40 GPa and the <I>Pm</I>3̅<I>m</I> structure of the α-phase becomes dominant (∼82 wt %) at 0.10 GPa but with an increased fraction of δ-FAPbI<SUB>3</SUB>. The photoluminescence behaviors from both the α- and δ-forms were likely controlled by radiative recombination at the defect levels rather than band-edge emission during pressure cycling. FAPbI<SUB>3</SUB> polymorphism is exquisitely sensitive to pressure. While modest pressures can engineer FAPbI<SUB>3</SUB>-based photovoltaic devices, irreversible δ-phase crystallization may be a limiting factor and should be taken into account.</P> [FIG OMISSION]</BR>

An Improved ViBe Algorithm of Moving Target Extraction for Night Infrared Surveillance Video

( Zhiqiang Feng ),( Xiaogang Wang ),( Zhongfan Yang ),( Shaojie Guo ),( Xingzhong Xiong ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.12

For the research field of night infrared surveillance video, the target imaging in the video is easily affected by the light due to the characteristics of the active infrared camera and the classical ViBe algorithm has some problems for moving target extraction because of background misjudgment, noise interference, ghost shadow and so on. Therefore, an improved ViBe algorithm (I-ViBe) for moving target extraction in night infrared surveillance video is proposed in this paper. Firstly, the video frames are sampled and judged by the degree of light influence, and the video frame is divided into three situations: no light change, small light change, and severe light change. Secondly, the ViBe algorithm is extracted the moving target when there is no light change. The segmentation factor of the ViBe algorithm is adaptively changed to reduce the impact of the light on the ViBe algorithm when the light change is small. The moving target is extracted using the region growing algorithm improved by the image entropy in the differential image of the current frame and the background model when the illumination changes drastically. Based on the results of the simulation, the I-ViBe algorithm proposed has better robustness to the influence of illumination. When extracting moving targets at night the I-ViBe algorithm can make target extraction more accurate and provide more effective data for further night behavior recognition and target tracking.

Short- and mid-term outcomes of transanal versus laparoscopic total mesorectal excision for low rectal cancer: a meta-analysis

Jingqing Ren,Huixing Luo,Shaojie Liu,Bailin Wang,Fan Wu 대한외과학회 2021 Annals of Surgical Treatment and Research(ASRT) Vol.100 No.2

Purpose: The current meta-analysis combining mid and low rectal cancer with no meta-analysis only for low rectal cancer was seen. This meta-analysis was to compare the short- and mid-term outcomes of the transanal total mesorectal excision (TaTME) vs. laparoscopic total mesorectal excision (LaTME) for low rectal cancer. Methods: A systematic literature search was conducted using the web-based databases; China National Knowledge Infrastructure, Chinese BioMedical Database, PubMed, Embase, Cochrane Central Register of Controlled Trials, and Wanfang Database. Randomized controlled trials (RCTs) were evaluated using the Jadad scale and non-RCTs (NRCs) were evaluated using the Newcastle-Ottawa Scale. Results: Ten studies (2 RCTs and 8 NRCs) involving 772 patients were included. Among them, 378 patients underwent TaTME and 394 patients underwent LaTME. Compared with the LaTME group, the conversion rate was low (risk ratio [RR], 0.25; 95% confidence interval [CI], 0.11–0.54; P < 0.001), the circumferential resection margin (CRM) involvement was low (RR, 0.48; 95% CI, 0.27–0.86; P = 0.010), and the hospital stay was short (mean difference, –1.72; 95% CI, –2.89 to –0.55; P = 0.004) in the TaTME group. No significant differences were seen in the mesorectal resection quality, CRM distance, distal resection margin (DRM) involvement, DRM distance, local R1 resection, intraoperative complications, morbidity, anastomotic leakage, severe morbidity, mortality, operative time, intraoperative blood loss, harvested lymph nodes, and local recurrence rate (P > 0.05). Conclusion: The TaTME is a promising surgical technique and is fully a safe and efficacious option in managing low rectal cancer.

Influence of Aeolian Sand on Capillary Water Absorption of Concrete Under Freeze–Thaw Conditions

Yugen Li,Huimei Zhang,Shaojie Chen,Hairen Wang,Xiaoyu Liu,Wei Gao 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.3

Aeolian sand (AS) can become a green resource for concrete after the reasonable utilization. Study the evolution of AS concrete (ASC) capillary water absorption (CWA) under freeze–thaw (FT) conditions is of great significance for its popularization and application. One-dimensional (1D) CWA test was performed to analyze the effects of AS and freeze–thaw cycling (FTC) on concrete water absorption characteristics. Pore relative saturation (PRS) and pore saturation were defined to reveal the influence mechanism of AS content on concrete water absorption under FT conditions and predict the moisture distribution in damaged ASC combining with the capillary mechanics theory. The results showed that concrete frost resistance increased with increased AS content and the optimal frost resistance achieved with 100% AS replacement despite its low strength. The initial water absorption rate (WAR), pore saturation, and saturation speed of the ASC decreased with increased AS, while the PRS increased with low AS content but decreased with excessive AS. The water absorption depth increased with increased mass and dynamic elastic modulus loss rates. The mechanism regarding why excessive AS improved concrete frost resistance lay in its internal pore structure and large pore ratio, which reduced pore content that can easily absorb water, enclosed a higher volume of air bubbles, and easily formed "air locking," thereby increasing water transmission resistance and forming long transmission paths during the process of CWA.

CONTROL STRATEGY FOR SHIFT SCHEDULE CORRECTION BASED ON DRIVING HABITS FOR VEHICLES WITH AUTOMATIC TRANSMISSION

Guang Xia,Jun Gao,Xiwen Tang,Shaojie Wang,Baoqun Sun 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.2

A shift schedule modification program is an intelligent system for automatic transmission. This program can adjust shift points to cater to drivers with different driving habits. An important prerequisite in designing a personalized shift schedule is identifying the driving habits of drivers. In this study, we developed an identification algorithm based on wavelet neural network and Bayesian fusion decision-making. First, a system for identifying driving styles was established based on the wavelet neural network. Second, the results were integrated by Bayesian fusion decision-making to obtain the driving habits. Finally, different correction coefficients were selected based on driving habits to satisfy the requirements of drivers. Experimental results show that the driving habits can be accurately identified based on wavelet neural network and Bayesian fusion decision-making, and the correction control strategy can rectify the shift schedule effectively. The correction control strategy satisfies the requirements of different drivers for vehicle performance and enhances the intelligence of automatic transmission.