Search

After two successive Baige landslides in the Jinsha River tectonic suture zone, a landslide scar with three steep free surfaces has been exposed in the source area, where three concomitant sliding blocks (K1, K2, and K3) have been identified as continuously moving at high rates, suggesting further potential failures within these areas. This study focused on structural geology and conducted a comprehensive multidisciplinary analysis to understand the active features and geological evolution models for these sliding blocks. Results showed that the three rockslides can be further subdivided into eleven subdomains. The revealed rock masses are likely to be affected by faults, fracture zones, and folds, and are featured by widely distributed and variable interbedded lithology with heterogeneous qualities combined with fragmentation, brecciation, and mylonitization. The movements are gradually increasing, especially encountering rainfall, and are ascribed to the dramatic unloading resulting from sudden large-scale detachments during the successive landslides and subsequent progressive time-dependent strength degradation of the rock masses. The active features and geological evolution models vary for the different subdomains and are intensely associated with daylighting geo-structures. Serpentinite predominates K1-4 and K1-5, showing brittle fracturing after a certain degree of accumulative deterioration is surpassed, highly weathered carbonaceous slate predominates K2-1 accompanied by “back-pushing” of en masse slide, and better rock mass integrity causes K1-3 to exhibit “fore-pulling” of retrogressive superficial collapse.

Background Triple-negative breast cancer (TNBC) accounts for 10–20% of all breast cancer cases. It represents an aggressive malignancy of frequently high histologic grade with no effective specific targeted therapies. Numerous studies have indicated that abnormal expressions of circRNAs may be a potential mechanism for the development and progression of cancer. CircRNAs may bind with miRNAs to influence the interaction between miRNAs and mRNAs and contribute to the progression of tumors, which was called as competitive endogenous RNA (ceRNA) hypothesis. In this study, we aimed to establish the ceRNA network in TNBC, and identify immune-related genes. Methods The circRNA (GSE101123), microRNA (TCGA-TNBC), and mRNA (TCGA-TNBC) expression profiles of TNBC were collected from the GEO database and TCGA database. Immune-related genes were collected from the ImmPort database. Differentially expressed circRNAs, miRNAs and mRNAs were identified. Then, the interacting relationships among circRNA-miRNA and miRNA-mRNA were predicted, and we constructed an immune-related ceRNA network. Subsequently, an immune-related signature was developed based on mRNAs in the ceRNA network. Results A total of 24 DEcircRNAs, 45 DEmiRNAs, 4814 DEmRNAs were identified. After overlapping DEmRNAs with immune-related genes, we obtained 490 immune-related DEmRNAs (DEIRGs). Then we took the intersection of 490 DEIRGs and 407 predicted miRNAs to obtain 5 immune-related mRNAs (IRGs). GO and KEGG pathway analysis showed that IRGs were associated with immunity. Then, an immune-related ceRNA network was constructed. Among the IRGs in ceRNA network, the AUC curve indicated that ADCYAP1R1, ANGPTL2, IL2RA and TGFBR2 with significantly diagnosis value were identified. Finally, we analyzed the correlation between 4 hub genes and immune infiltrating cells, ADCYAP1R1 were negatively associated with Type 2 T helper cell. Conclusion We screened the key genes and established an immune-related ceRNA network involved in TNBC, which will assist in understanding the molecular mechanisms underlying the carcinogenesis and progression.

At 8:30 a.m., on August 11, 2018, a high-position rockslide avalanche was reported in Da’anshan village, Fangshan district, Beijing, China. The landslide destroyed the road below and did not cause any casualties due to the timely detection of warning signs. The displaced landslide material traveled a horizontal distance of about 260 m with a vertical drop of about 176 m and stopped at 613.6 m asl. According to videos and survey data, the Da’anshan rockslide initiated at a high position and transformed into a pipeline-type debris avalanche along the gully to the east. It scraped the surface layer of the strongly weathered rock formation and also transformed into a diffuse-type debris flow along the slope surface. Finally, it accumulated at the bottom of the river valley and presented a typical disaster mode of rapid runout. Based on this, the Archard erosion model was embedded in the Engineering Discrete Element Method (EDEM) to perform back analysis and simulate the three-stage kinematic processes of sliding, shear-shoveling, and flow accumulation to quantify the scraping volume and position. After initiation at a high-level position, the rockslide moved downward along the valley for approximately 10 s with a maximum velocity of 26.1 m/s. The final volume of the accumulation obtained from the simulation was ~24,000 m3, which is close to the total volume obtained from the field investigations. This study provides a methodological reference for future simulation analysis of high-position rockslide avalanches.

This paper provides newly found and profound insight into the initiation mechanism of the first Baige landslide occurred on the upper reaches of the Jinsha River in October 10, 2018. The detailed geological characteristics are interpreted by comprehensive field surveys in the past year, which indicate that the Baige landslide developed in the Jinsha River tectonic suture zone, and the active tectogenesis significantly contributes to broken stratigraphic structures and complex spatial distribution of lithologies. The initiation is considered to be long-term creep under the exogenic and endogenic integration, while the active tectogenesis and the influence of serpentinite and foliation, respectively, are the primary exogenic and endogenic factors. In addition, this creep process can be analyzed within three stages: evolution and formation of failure-prone geological structures, progressive deformation and fracturing, and shear failure of the locking section. The distribution and easily degraded behavior of the serpentinite are the fundamental, enabling the formation of failure-prone structures and also responsible for the subsequent deformation evolution. The foliation controls the toppling deformation-failure mode and direction. Furthermore, this catastrophic landslide further reminds us to pay attention to the landslides along the upper reaches of the Jinsha River, and our preliminary results indicate that the distribution characteristics of landslides significantly depend on the Jinsha River tectonic suture zone and the serpentinite melange belt and thus are always associated with tectonically induced damage.

The design of the human habitat can either promote or oppose healthy living, sustainable lifestyles, and the ability to value nature in people. The goal of this paper is to provide some insights to...

A catastrophic landslide hit Mount Fugui, Diexi Township, Mao County, Sichuan Province, at 05:38:58 on June 24, 2017. This landslide buried Xinmo Village, caused 83 deaths, and resulted in enormous losses of life and property. The landslide mass cut out and slid from a high position, loaded continuously, and accumulated at the top of the slope body. Subsequently, the landslide mass was transformed into avalanche debris. This process was a typical chain disaster of avalanche debris triggered by a ridge-top landslide. The total volume, elevation difference, and horizontal distance of the landslide were 1637.6 χ 104 m3, 1200 m, and 2800 m. In this research, the disaster-formation mechanism of the Xinmo Landslide was identified based on a geological field survey and remote sensing satellites. The disaster characteristics of the landslide source zone, debris avalanche zone, and accumulation zone were then numerically simulated. The entire process of the Xinmo Landslide movement was comparatively studied using DAN-W, a dynamic landslide software program, and multiple rheological models. The research findings indicated that the frictional model favorably simulated the movement characteristics of various phases of the Xinmo Landslide. This landslide lasted approximately 120 s, and it had a maximum velocity of movement of 74 m/s. Therefore, the frictional model and its parameters can be used in similar studies to investigate the dynamic disaster effects of ridge-top rock landslides. RESUMEN Un deslizamiento de tierra catastrófico afectó el Monte Fugui, de la localidad Diexi, en el condado Mao de la provincia china de Sichuan, a las 05:38:58 hora local del 24 de junio de 2017. Este deslizamiento enterró la población de Xinmo, causó 83 muertos y significó enormes pérdidas de propiedades. La masa del deslizamiento se desprendió en lo alto de la montaña, se continuó cargando y se acumuló en la parte alta de la pendiente. Seguidamente, la masa del deslizamiento se transformó en una avalancha de detritos. Esta fue una cadena típica de un desastre ocasionado por una avalancha de detritos que comenzó por un deslizamiento en lo alto de la montañana. El volumen total, la diferencia de elevación y la distancia horizontal del deslizamiento fueron de 1637.6 χ 104 m3, 1200 m, and 2800 m. En este trabajo se identificó el mecanismo de formación del deslizamiento de Xinmo con base en un estudio de campo geológico y con el apoyo de satélites de teledetección. Los autores simularon numéricamente las características del desastre en la zona fuente, en la zona de la avalancha y en la zona de acumulación. Todo el proceso del deslizamiento de Xinmo fue estudiado comparativamente con el programa DAN-W, que analiza dinámicas de deslizamiento, y múltiples modelos reológicos. Los resultados del estudio indican que el modelo friccional simuló favorablemente las características del movimiento en varias fases del deslizamiento de Xinmo. Este movimiento duró por lo menos 120 segundos, y tuvo una velocidad máxima de movimiento de 74 m/s. Además, el modelo friccional y sus parámetros se pueden usar en estudios similares para investigar los efectos dinámicos de un movimiento de tierra en la parte alta de una montaña.

Submerged rock masses in reservoir areas can be dangerous when the base rock mass is located in a deterioration zone formed by periodic water level fluctuations. Deformation of the base rock mass is driven by compression due to its own overlying weight and the hydrological conditions of the reservoir; the combination of these two factors represents a complex mechanical environment. This hydraulic coupling accelerates the deterioration and the instability of the base rock mass. To investigate the Jianchuandong dangerous rock mass (JDRM) in the Three Gorges Reservoir area, we devised a new hydraulic coupling mechanism that, when applied to a generalized mechanics model, represents the mechanical environment of the base rock mass in the deterioration zone. In this hydraulic coupling mechanism, when water is in direct contact with the rock mass, the water pressure contributes to the expansion of existing fractures in the JDRM base rock mass. With this hydraulic coupling mechanism, we created a constitutive damage model that reflects the observed stress-strain characteristics of the JDRM base rock mass in these hydrological conditions. After refining our model by incorporating the damage experienced by the submerged dangerous rock mass over time, we determined that the eventual failure of the JDRM can be divided into three stages: the formation of the bottom damage zone, progressive deformation and damage, and sudden rock collapse. Our model indicates that the damage can magnify the effective stress experienced by the base rock mass and lead to the nonlinear acceleration of the deterioration of the dangerous rock mass.

Syringa wolfii (Syringa: Syringeae), an upright shrub, is ornamental species used in urban greenification. In this study, we determined the complete chloroplast (cp) genome of S. wolfii using next-generation sequencing (NGS). The size of the chloroplast genome is 156,571 bp in length, including a large single-copy region (LSC) of 86,684 bp, a small single-copy region (SSC) of 19,109 bp, and a pair of inverted repeat (IR) regions with 25,362 bp. The GC content of the chloroplast genome was 37.95%. Moreover, a total of 131 functional genes were annotated, including 87 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. The neighbor-joining phylogenetic tree suggested that S. wolfii was closely related to S. yunnansis.

Syringa reticulata subsp. pekinensis (Ruprecht) P. S. Green & M. C. Chang (Oleaceae: Syringeae) is horticultural woody plant. To grasp a better comprehension on the molecular basis of S. reticulata...

After the first high-position landslide occurred in Baige Village, a second slide originated from the crown of the first landslide on November 3. The approximately 1.6 million m3 second slide moved rapidly and applied an impact load on the upper part of the residual mass of the first landslide, resulting in a 6.6 million m3 entrainment volume. The sliding mass rushed into the Jinsha River and blocked the channel again, causing catastrophic flooding which destroyed numerous roadbeds, bridges, and a large number of residential houses in Sichuan and Yunnan provinces. Based on field investigations and simulation results by dynamic discrete element method (DEM), after the first landslide, the blocks formed by the trailing edge of the landslide became unstable and slid, continuously and dynamically loading and accumulating on the upper part of the first debris deposit, which rested in the grooved terrain of the slope, leading to the instability of the residual slope’s rock–soil mass and the initiation of a debris avalanche. With a peak velocity of 62 m/s, the debris avalanche slid rapidly to the location of the first slide deposit. Due to the topographic effect, it was transformed into a diffused debris avalanche, which scattered and accumulated, exhibiting the typical characteristics of a rapid long-runout landslide. Then, the calculated velocity value by DEM was also compared with those using other dynamic modeling approaches (e.g., sled model and rheological model). The DEM was proven producing a reasonable velocity variation pattern, and thus, it is suitable for the simulation of the entire movement process of high-position rockslides similar to the second Baige landslide.

At 5:38:58 a.m. on June 24, 2017, a catastrophic rockslide avalanche occurred at the Xinmo village, Diexi town, Maoxian county, Sichuan Province, and the area could have been deeply affected by many strong earthquakes in history. The landslide killed 83 people and destroyed the whole village, with the runout horizontal distance of about 2800 m and the elevation difference of 1200 m, which was equivalent to a Fahrboschung of about 23°, and the accumulative volume reached nearly 18 million m3. The field investigation and preliminary analysis of landslide seismic signals indicated that, after sliding from the ridge crest, the rock mass continuously impacted and accumulated on the upper part of the slope, which caused the substrate, i.e., old rockslide accumulation, to slide and disintegrate. It was transformed rapidly into a pipeline-type debris avalanche that then turned into a fan-like debris flow due to the terrain, which also had the typical dynamic characteristics of high speed and long runout. However, in fact, as the cause and effect of the kinematic and dynamic processes of the Xinmo landslide is so complicated and difficult to understand, the Fast Lagrangian Analysis of Continua (FLAC) and the slope-stability analysis module of GeoStudio were firstly combined to analyze the failure process of the old rockslide accumulation body when suffering the added forces from the landslide. Then, the Engineering Discrete Element Method (EDEM) was used to simulate the runout behavior of the displaced landslide materials, the calculated velocity value of which was also compared with those using other dynamic modeling approaches (e.g., sled model, rheological model, and liquefied model). The results demonstrate that the dynamic characteristics and the kinetic type of the Xinmo landslide were successfully simulated. Besides, the velocity values simulated by EDEM and by the rheological model were close to the value of around 60 m/s based on the distance of debris avalanche and the corresponding duration recognized through landslide seismic signals. Also, their velocity variation curves with motion were rational. The above proposed method can be further applied for studies on early recognition and hazard zonation of similar large-scale rockslide avalanches in areas affected by strong earthquakes.

Strongylocentrotus intermedius is one of the most economically valuable sea urchin species in China, and its growth and survival are severely constrained by ocean warming and the hypoxia that often accompanies high water temperatures. To elucidate the molecular mechanisms of S. intermedius that regulate gene expression in response to multi-causal environmental stresses. We performed a de novo transcriptome analysis of coelomocyte from S. intermedius to heat (25 °C), hypoxia (2 mg/L), and the combined stress. We identified 35,635, 29,107, and 29,440 differentially expressed genes (DEGs) in S. intermedius cultured under high temperature, low oxygen, and combined stress, respectively. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analyses revealed that these DEGs mainly enriched the functional categories of "Protein processing in endoplasmic reticulum," and "Glutathione metabolism" by heat stress, such as HSP70, GSTO1, PDIA4. After hypoxic stress, "Notch signaling pathway" and metabolism-related pathways such as "Glycerolipid metabolism", "Pyruvate metabolism" were significantly enriched. Exposure to combined stress resulted in a two-factor additive effect at the transcriptome level and have a more extensive impact on the immune correlated pathways in S. intermedius than single stress, the expression of related immune genes (C3, C5, and AIFM2) were up-regulated. Quantitative real-time PCR (qRT-PCR) analysis of the expression of 18 DEGs confirmed the RNA-Seq results. Observations in the present study will improve the understanding of the molecular mechanism of S. intermedius in response to multi-causal environmental stress.

In the analysis reported here, the catastrophic landslide at Areletuobie town in Xinyuan county is used as an example to investigate the formation mechanism and dynamics of a flow-like landslide in Yili River valley. At 0:30 a.m. on July 31, 2012, a catastrophic landslide occurred in Xinyuan, Xinjiang, northwestern China, resulting in the deaths of 28 people when the temporary sheds in the downstream adit mining area were destroyed and buried directly in the path of the landslide. The runout distance of the landslide was about 1800 m, and the accumulative volume was about 600,000 m3. The landslide can be categorized into three regions: the sliding source, impact-shoveling, and flow-accumulative regions. The stability of the landfill slope in the sliding source region was analyzed at two seepage stages of a long period of rain and a sudden heavy rainfall. To improve the accuracy of further hazard assessments of similar types of potential landslides in the same area, we simulated the kinematic and dynamic processes of the impact-shoveling region and the debris flow using the numerical model DAN-W and a combination of the frictional model and Voellmy model. The landslide moved for approximately 139 s downward along the valley, with a maximum velocity of 30 m s−1. This is a typical long-runout flow-like landslide. Finally, we conclude that the identification of the potential geological hazards at Yili River valley area is crucial to prevent any catastrophic flow-like landslide triggered by heavy rainfall. The identified indicators should be properly used as a scientific basis for classifying hazard areas of flow-like landslides as well as for monitoring and early recognition.

The 2008 Ms 8.0 Wenchuan earthquake triggered a large number of extensive landslides. It also affected geologic properties of the mountains such that large-scale landslides followed the earthquake, resulting in the formation of a disaster chain. On 10 July 2013, a catastrophic landslide–debris flow suddenly occurred in the Dujiangyan area of Sichuan Province in southeast China. This caused the deaths of 166 people and the burying or damage of 11 buildings along the runout path. The landslide involved the failure of ≈1.47 million m3, and the displaced material from the source area was ≈0.3 million m3. This landslide displayed shear failure at a high level under the effects of a rainstorm, which impacted and scraped an accumulated layer underneath and a heavily weathered rock layer during the release of potential and kinetic energies. The landslide body entrained a large volume of surface residual diluvial soil, and then moved downstream along a gully to produce a debris flow disaster. This was determined to be a typical landslide–debris flow disaster type. The runout of displaced material had a horizontal extent of 1200 m and a vertical extent of 400 m. This was equivalent to the angle of reach (fahrboschung angle) of 19° and covered an area of 0.2 km2. The background and motion of the landslide are described in this study. On the basis of the above analysis, dynamic simulation software (DAN3D) and rheological models were used to simulate the runout behavior of the displaced landslide materials in order to provide information for the hazard zonation of similar types of potential landslide–debris flows in southeast China following the Wenchuan earthquake. The simulation results of the Sanxicun landslide revealed that the frictional model had the best performance for the source area, while the Voellmy model was most suitable for the scraping and accumulation areas. The simulations estimated that the motion could last for ≈70 s, with a maximum speed of 47.7 m/s.

Two successive Baige landslides are presented in this study to investigate the dynamics and emplacement mechanisms. Field survey shows that the deposit characteristics of the first landslide are affected by the extremely fractured rock masses and the complex spatial distribution of lithologies in the source area. This deposit consists of abundant angular megablocks on the surface supported by clasts, with a relatively abundant content of rubble ranging from micrometre to decimetre sizes, and rarely well-preserved original stratigraphic sequence, diapiric structure, and convoluted structure. These sedimentological characteristics imply that a simple differential shear process, induced by compression, is distributed through the entire avalanche masses with low internal disturbance during the emplacement of the first landslide. The three-dimensional discrete element simulations show that: (i) the first landslide reaches its maximum average velocity of 41 m/s in ~28 s and eventually is bulldozed to a halt in the river within ~80 s. (ii) The second landslide is controlled by entrainment, which impedes the avalanche from further accelerating, and simultaneously imparts kinematic energy to the substrate, eventually becoming entirely mobilized and reaching a maximum average velocity of 35 m/s in ~36 s. In the dynamic process of the second landslide, the significant entrainment-induced enlarged volume (its entrainment ratio reaches 3.3) is associated with the steep concave terrain, water-bearing substrate and lower-roughness substrate basal boundary, and overloading-impact-induced erosion is proposed to be the most significant contribution to this entrainment.

This paper presents findings from an investigation of the large-scale construction solid waste (CSW) landslide that occurred at a landfill at Shenzhen, Guangdong, China, on December 20, 2015, and which killed 77 people and destroyed 33 houses. The landslide involved 2.73×106 m3 of CSW and affected an area about 1100 m in length and 630 m in maximum width, making it the largest landfill landslide in the world. The investigation of this disaster used a combination of unmanned aerial vehicle surveillance and multistage remote-sensing images to reveal the increasing volume of waste in the landfill and the shifting shape of the landfill slope for nearly two years before the landslide took place, beginning with the creation of the CSW landfill in March, 2014, that resulted in the uncertain conditions of the landfill's boundaries and the unstable state of the hydrologic performance. As a result, applying conventional stability analysis methods used for natural landslides to this case would be difficult. In order to analyze this disaster, we took a multistage modeling technique to analyze the varied characteristics of the landfill slope's structure at various stages of CSW dumping and used the non-steady flow theory to explain the groundwater seepage problem. The investigation showed that the landfill could be divided into two units based on the moisture in the land: a front uint, consisted of the landfill slope, which had low water content; and a rear unit, consisted of fresh waste, which had a high water content. This structure caused two effects—surface-water infiltration and consolidation seepage that triggered the landslide in the landfill. Surface-water infiltration induced a gradual increase in pore water pressure head, or piezometric head, in the front slope because the infiltrating position rose as the volume of waste placement increased. Consolidation seepage led to higher excess pore water pressures as the loading of waste increased. We also investigated the post-failure soil dynamics parameters of the landslide deposit using cone penetration, triaxial, and ring-shear tests in order to simulate the characteristics of a flowing slide with a long run-out due to the liquefaction effect. Finally, we conclude the paper with lessons from the tens of catastrophic landslides of municipal solid waste around the world and discuss how to better manage the geotechnical risks of urbanization.

This study presents a combined anti-sliding structural system of micropile groups, with an arched shape on the plane and cement paste between the micropiles, in the Tizicao high-position landslide study conducted in the Wenchuan seismic area, China. Improvements in the landslide’s stability as a result of the embedded micropile groups alone and in combination with long prestressed anchor cables are studied using FD-SRM and FOS contour analysis methods, respectively. The soil arching effect and the load sharing of the arched micropile group are analyzed using the numerical simulation method. Findings show that the arching effect is due to arc-shaped arrangements of the micropile groups. The design scheme of the embedded micropile groups improves the stability of this kind of thickly layered, high-position landslide. Moreover, its construction is convenient and the mechanism is clear, making it a good engineering reference for the treatment of similar landslides. The improvement in the landslide’s stability is even better than that achieved by the combination of micropile groups and long prestressed anchor cables. Furthermore, the arching effect of multiple rows of micropile groups is significant and can effectively block the movement of the sliding body. The load transfer involved in the micropile–soil interaction process is a new type of two-part load sharing pattern. The soil arching behind the micropile groups takes more than 80% of the total load. A tangential tension zone appeared along the top of the pile–group arc crown when the arch protruded upward, and a related structural performance design should be considered in the future.

This paper uses the catastrophic rockslide at Sanxicun village in Dujianyan city as an example to investigate the formation mechanism of a rapid and long run-out rockslide-debris flow of fractured/cracked slope, under the application of a rare heavy rainfall in July 2013. The slope site could be affected by the Wenchuan Ms 8.0 Earthquake in 2008. The sliding involved the thick fractured and layered rockmass with a gentle dip plane at Sanxicun. It had the following formation process: (1) toppling due to shear failure at a high-level position, (2) shoveling the accumulative layer below, (3) forming of debris flow of the highly weathered bottom rockmass, and (4) flooding downward along valley. The debris flow destroyed 11 houses and killed 166 people. The run-out distance was about 1200 m, and the accumulative volume was 1.9 × 106 m3. The rockslide can be divided into sliding source, shear-shoveling, and flow accumulative regions. The stability of this fractured rock slope and the sliding processes are discussed at four stages of cracking, creeping, separating, and residual accumulating, under the applications of hydrostatic pressure and uplift pressure. This research also investigates the safety factors under different situations. The double rheological model (F-V model) of the DAN-W software is utilized to simulate the kinematic and dynamic processes of the shear-shoveling region and debris flow. After the shear failure occurred at a high-level position of rock, the rockslide moved for approximately 47 s downward along the valley with a maximum velocity of 35 m/s. This is a typical rapid and long run-out rockslide. Finally, this paper concludes that the identification of the potential geological hazards at the Wenchuan mountain area is crucial to prevent catastrophic rockslide triggered by heavy rainfall. The identified geological hazards should be properly considered in the town planning of the reconstruction works.

China Geological Survey (CGS) is one of the 15 new World Centres of Excellence (WCoE) in Landslide Disaster Reduction for the period 2014–2017. The title of the activities of the WCoE has been “Scientific research for mitigation, preparedness and risk assessment of landslides” since 2008, due to the complex conditions for the occurrence of geohazards in China. The Center of Geohazards Emergency of Ministry of Land Resources, which is directly under CGS, is responsible for the emergency response to major geohazards nationwide, including survey and investigation, monitoring and warning, risk assessment, prevention, training, and information systems. In this paper, the important activities of CGS are elaborated. The research project entitled “Research Project on the Early Recognition and Warning on Heavy Rainfall-Induced and Hydraulic-Driven Geological Hazards in China” was conducted from 2011 to 2015. From 2015 to 2017, a new project on mechanisms and hazards patterns of hydraulic-driven landslides has been conducted by the Center of Geohazards Emergency, China Geological Survey.

This paper discusses the effect of the May 12, 2008 Wenchuan earthquake on a landslide where stabilization work had taken place and compares the results to sites without stabilization. Contours of shear strain increment and displacement values obtained using a FLAC3D simulation show that the Wangjiayan landslide, which had stabilization work, was stable before the Wenchuan earthquake. Simulations using input strong motion accelerations from the main shock recorded at Qingping station, within the main seismic fault zone, suggest a shear strain increment about 3,000 times more than it was before the main shock. Although the stability of the stabilized landslide decreased during the earthquake, the displacement values were very small. Modeled displacements suggest that the piles played a major role in keeping the slope from sliding. The anti-slide piles were subjected to high shaking acceleration. The strong ground motion records for a time range of 10 to 30 s show that the piles generally experienced accelerations in the range from 0.0 to 3.0 g, with a few spikes of about 5.0 g. Special observation stations were set up to monitor the slope motion at Qingchuan town, 150 km far from the Wangjiayan landslide, along the main central seismic fault zone, after the Wenchuan earthquake. The variation in acceleration with time and the FOS versus time of the Wangjiayan landslide were investigated using these acceleration records of the aftershocks as input data. The aftershock accelerations did not decrease the stability of the Wangjiayan landslide, but an amplification effect on the acceleration of the slope at different elevations was illustrated.

At 11:40 a.m., December 20, 2015, a catastrophic landslide occurred in Shenzhen, Guangdong, Southeast China. Seventy-seven people were killed, and 33 buildings were buried or damaged, which were in the direct path of the landslide at the Guangming New District. The landslide involved 2.73 million m3 of the municipal solid waste (MSW) and had a horizontal runout distance of 1100 m, over a vertical distance of 113 m, which was equivalent to a Fahrboschung of 6°, and covered an area of 0.38 km2. Basic post-failure characteristics are described in this study. Dynamic simulation software (DANW) and rheological models were used to simulate the runout behavior of the displaced landslide material, in order to provide information for the hazard zonation of similar types of potential MSW landslides. The simulated results revealed that a combination of the frictional model and Voellmy model is able to provide the best performance in simulating this landslide. Also, the results showed that this landslide had a duration of about 50 s, with a maximum velocity of 22.4 m/s. It was expected that these models and parameters could improve the accuracy of future hazard assessments of areas with geological, topographical, and climatic features similar to the Shenzhen Hong’ao landfill.

This paper proposes the stochastic isogeometric analysis (IGA) method in conjunction with the perturbation technique for random response analysis of plate structures. Specifically, the benchmark solutions of stochastic deflection responses for rectangular plate are achieved. Firstly, the random field is represented by Karhunen-Loeve expansion, and the corresponding analytical formulas of the Fredholm integral equation for rectangular plate are illustrated to obtain the benchmark stochastic responses. Subsequently, the stochastic IGA framework is suggested by combining isogeometric analysis with the first-order perturbation technique, especially for the bending problems of circular Mindlin plates and Kirchhoff plates. Moreover, the first two moments of stochastic responses of plate structures are formulated. Finally, the efficiency and applicability of the stochastic IGA method are demonstrated by three numerical examples. To compare with the efficiency and accuracy of proposed method, the mean values, standard deviations and coefficients of variation of stochastic responses are calculated by Monte Carlo simulation. For the rectangular and circular Kirchhoff thin plates, the effects of different correlation lengths, boundary conditions and loading cases on stochastic responses and uncertainty propagation are scrutinized. It is also indicated that the proposed stochastic IGA method presents high efficiency and acceptable accuracy of random structural analysis of plates.

This paper theoretically investigates the signal degradation induced by intersubcarrier interference and frequency-selective fading in orthogonal frequency-division-multiplexing radio-over-fiber systems. Turbo codes and bit interleaver technologies are proposed to effectively mitigate unbalanced error distribution because of intersubcarrier interference and frequency-selective fading. Experimental results show that the receiver sensitivities are improved as far as 5 dB after 50-km SMF-28 transmission for 6.25-Gb/s wireless signals on optical generated 60-GHz carrier.

Interleaver and turbo code techniques are used in high spectral-efficient direct-detection optical orthogonal frequency-division-multiplexing (OFDM) transmission systems allowing significant improvement of optical receiver sensitivity by mitigating the unbalanced noise distribution in subcarrier signals. The optical signal-to-noise ratio of 5.18 Gb/s, 7.77-Gb/s coded OFDM (5.18 Gb/s after decoding), and 7.77-Gb/s coded OFDM with interleaver (5.18 Gb/s after decoding) over 200-km single-mode fiber at a bit-error rate of 10-4 are 23.7, 18.0, and 17.1 dB, respectively.

A variety of seismic design methods for subway structures, which are present popular in China, are introduced, including the response displacement method (RDM), modified cross section racking deformation method (MCSRDM), the response acceleration method (RAM) and the pushover analysis method (PAM). A comparison calculation was then made for the same typical subway structural cross-section under the same typical geological conditions in Beijing by use of all above methods and dynamic time history analysis method. It was shown that the calculated results gained from the RDM, whose coefficient of dynamic subgrade reaction was based on Japanese railway earthquake-resistance designing code or static finite element, the MCSRDM, the RAM and the PAM were close to that from the dynamic analysis method. It provided some reference for practical seismic design of subway structures in the future.

We demonstrate a novel low-cost radio-over-fiber network architecture with one directly modulated laser and one intensity modulator. By employing an orthogonal frequency division mutiplexing modulation format and frequency quadruple scheme, the bandwidth requirement of the devices and the cost of the system is reduced. Experimental results show that the power penalty for the downlink data after transmission over 20-km single mode optical fiber (SMF)-28 is smaller than 1.3 dB, while for the up-link data, the power penalty after transmission over 20-km SMF-28 is smaller than 0.3 dB.