scholarly journals The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure

2021 ◽  
Vol 9 (5) ◽  
pp. 1263-1277
Author(s):  
Xiangang Jiang ◽  
Haiguang Cheng ◽  
Lei Gao ◽  
Weiming Liu
Keyword(s):  
Field Data ◽  
Failure Process ◽  
Landslide Dam ◽  
Dam Failure ◽  
Dimensionless Length ◽  
Channel Changes ◽  
Outburst Floods ◽  
Characteristics Analysis ◽  
Movable Bed ◽  
The Relationship

Abstract. Boulder bars are a common form of riverbed morphology that could be affected by landslide dams. However, few studies have focused on the formation and geometry characteristics of boulder bars due to outburst floods triggered by landslide dam failure. In such a way, eight group landslide dam failure experiments with a movable bed length of 4 to 7 times the dam length with 25 boulder bars were carried out. In addition, 38 boulder bars formed in the field triggered by four landslide dam failures were investigated. The aim of this paper is to study the formation and geometry characteristics of boulder bars along the riverbeds. The results show that boulder bars are formed after peak discharge of outburst flow. The number of boulder bars is 0.4 to 1.0 times the ratio of riverbed length to dam bottom length. Besides, boulder bars have the characteristic of lengthening upstream during the failure process. A boulder bar's upstream edge has a more extensive development than a boulder bar's downstream edge. The length of a boulder bar along the channel changes faster than the boulder bar's width and height. After the dam failure, the boulder bar's length is about 8 to 14 times its width. The relationship between the ratio of boulder bar length to width and the boulder bar's dimensionless length could be described with a hyperbolic equation. The dimensionless area of the boulder bar increases linearly with the dimensionless area of the river section, and the linear ratio is about 0.5. With the field data, this demonstrates that the formation and geometry characteristics of boulder bars in tests are consistent with the field boulder bars. Therefore, the results in this paper are credible and can be applied to the riverbed's geomorphological characteristics analysis triggered by overtopped landslide dam failure. The plentiful experimental and field data could contribute to the community boulder bar research.

The maximum discharge of outburst floods caused by the breaching of man-made and natural dams

1986 ◽  
Vol 23 (3) ◽  
pp. 385-387 ◽  
Author(s):  
Stephen G. Evans
Keyword(s):  
Empirical Relationship ◽  
Landslide Dam ◽  
Dam Failure ◽  
Order Estimate ◽  
Mountainous Regions ◽  
Maximum Discharge ◽  
Outburst Floods ◽  
Debris Dams ◽  
Sudden Release ◽  
The Relationship

The sudden release of water impounded in natural and man-made reservoirs has been responsible for some major disasters in mountainous regions of the world. Recent natural damming events and failures of natural dams have illustrated the need to examine the nature and magnitude of outburst floods and the behaviour of debris dams in general. An empirical relationship between maximum discharge (Qmax) and volume of water released during the outburst event (Vmax) is established (Qmax = 0.72Vmax0.53) for man-made dams and the relationship is thought applicable to the breaching of natural debris dams (landslides and moraines). This relationship allows a first-order estimate to be made of Qmax in the vicinity of the breach for a given Vmax during the failure of a man-made dam or a natural debris dam. Key words: outburst floods, man-made dams, natural dams, landslide, dam failure.

scholarly journals The formation processes and development characteristics of sandbars due to outburst flood triggered by landslide dam overtopping failure

2020 ◽  
Author(s):  
Xiangang Jiang ◽  
Haiguang Cheng ◽  
Lei Gao ◽  
Weiming Liu
Keyword(s):  
Failure Process ◽  
Landslide Dam ◽  
Dam Failure ◽  
Average Height ◽  
Formation Processes ◽  
Outburst Flood ◽  
Channel Changes ◽  
River Bed ◽  
Essential Form ◽  
Overtopping Failure

Abstract. Sandbars are an essential form of riverbed morphology which could be affected by landslide dams. However, few studies have focused on the formation processes and development characteristics of sandbars triggered by outburst flood. In such a way, eight group dam failure experiments with 4 to 7 times of dam length movable bed is carried out to study the temporal and spatial distributions of 25 sandbars along the riverbeds, the sandbars geometric characteristics, and the influence of outburst flow hydraulic characteristics on developments of sandbars. The results show that sandbars are formed after peak discharge of outburst flow. The number of sandbars is 0.4 to 1.0 times the ratio of river bed length to dam length. Besides, sandbars have the characteristic of lengthening towards upstream during the failure process. Sandbars' upstream edges have a more extensive development than sandbars downstream edges. The length of a sandbar along the channel changes faster than the sandbar's width and height. The sandbars' length and width are about 10 to 80 and 1 to 7 times of average height, respectively, and the average heights of sandbars are about 1 to 3.5 times the maximum particle size. Sandbars' lengths make a more significant impact on sandbars' volumes than widths and heights. It found that the Froude number has a significant influence on the sediment carrying capacity. And the sediment concentrations in volumes of the outburst flow at the upstream edges of all sandbars are greater than those at the downstream edges of sandbars. Meanwhile, the sediment carrying capacities of the outburst flow at the upstream edges of sandbars are smaller than those at the sandbars' downstream edges. And the differences between the sediment concentrations and the sediment carrying capacities determine the sedimentation or entrainment. The results can reference the research on the river channel's geomorphological characteristics affected by the outburst flood.

scholarly journals A Preliminary Study of the Failure Modes and Process of Landslide Dams Due to Upstream Flow

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1115 ◽  
Author(s):  
Xinghua Zhu ◽  
Jianbing Peng ◽  
Cheng Jiang ◽  
Weilong Guo
Keyword(s):  
Large Scale ◽  
Failure Modes ◽  
Mine Waste ◽  
Failure Process ◽  
Landslide Dam ◽  
Experimental Tests ◽  
Field Investigation ◽  
Dam Failure ◽  
Experimental Conditions ◽  
Landslide Dams

In the process of mineral development, large-scale flash floods (or debris flows) can be induced by the failure of landslide dams formed by the disorganized stacking of mine waste. In this study, the modes and processes of mine waste dam failures were explored using 13 experimental tests based on the field investigation of landslide dams in the Xiaoqinling gold mining area in China. Our 13 mine waste dam experiments exhibited three failure modes: (i) Piping, overtopping, and erosion; (ii) overtopping and soil collapse; and (iii) overtopping and erosion. In addition, the failure processes of the landslide dams included impoundment, seepage, overtopping, and soil erosion. Different experimental conditions would inevitably lead to different failure processes and modes, with the failure modes being primarily determined by the seepage characteristics. Overtopping was the triggering condition for dam failure. The landslide dam failure process was determined based on the particle size of the mine waste and the shape of the dam. These findings will provide a scientific reference for the prevention and mitigation of natural hazards in mining areas.

scholarly journals Large-Scale Field Test Study on Failure Mechanism of Non-Cohesive Landslide Dam by Overtopping

2021 ◽  
Vol 9 ◽  
Author(s):  
Liang Li ◽  
Xingguo Yang ◽  
Jiawen Zhou ◽  
Jieyuan Zhang ◽  
Gang Fan
Keyword(s):  
Large Scale ◽  
Discharge Channel ◽  
Failure Process ◽  
Field Tests ◽  
Landslide Dam ◽  
Development Stage ◽  
Dam Failure ◽  
Process Time ◽  
Scale Field ◽  
Large Scale Field

In recent years, landslide lake disasters occur frequently in southwest mountainous areas of China. Considering the influence of dam size and discharge channel location, three large-scale field tests were carried out in a natural river to study the failure process and mechanism of non-cohesive soil landslide dam, and the process and mechanism of non-cohesive landslide dam breach were analyzed. The results show that the dam size and discharge channel location have a significant influence on the breach mechanism of the landslide dam. The dam failure process can be divided into three stages: the initiation stage, the development stage and the failure stage. When the discharge channel is located close to the bank, the width of the breach is smaller, and the volume of the residual dam body is larger. The more stable the dam body is, the longer the breach process time is, and the smaller the peak discharge is. This study can provide a scientific reference for the emergency disposal and risk assessment of landslide dam.

scholarly journals Geomorphic effects of recurrent outburst superfloods in the Yigong River on the southeastern margin of Tibet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kaiheng Hu ◽  
Chaohua Wu ◽  
Li Wei ◽  
Xiaopeng Zhang ◽  
Qiyuan Zhang ◽  
...  
Keyword(s):  
Landslide Dam ◽  
Upstream Migration ◽  
One Dimensional ◽  
Landform Evolution ◽  
Outburst Floods ◽  
Stepwise Method ◽  
Large Landslide ◽  
Southeastern Margin ◽  
Channel Slope ◽  
The One

AbstractLandslide dam outburst floods have a significant impact on landform evolution in high mountainous areas. Historic landslide dams on the Yigong River, southeastern Tibet, generated two outburst superfloods > 105 m3/s in 1902 and 2000 AD. One of the slackwater deposits, which was newly found immediately downstream of the historic dams, has been dated to 7 ka BP. The one-dimensional backwater stepwise method gives an estimate of 225,000 m3/s for the peak flow related to the paleo-stage indicator of 7 ka BP. The recurrence of at least three large landslide dam impoundments and super-outburst floods at the exit of Yigong Lake during the Holocene greatly changed the morphology of the Yigong River. More than 0.26 billion m3 of sediment has been aggraded in the dammed lake while the landslide sediment doubles the channel slope behind the dam. Repeated landslide damming may be a persistent source of outburst floods and impede the upstream migration of river knickpoints in the southeastern margin of Tibet.

scholarly journals A Field Measurement Based Wind Characteristics Analysis of a Typhoon in Near-Ground Boundary Layer

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 873
Author(s):  
Dandan Xia ◽  
Liming Dai ◽  
Li Lin ◽  
Huaifeng Wang ◽  
Haitao Hu
Keyword(s):  
Turbulence Intensity ◽  
Field Measurement ◽  
Three Dimensional ◽  
Wind Data ◽  
Statistical Characteristics ◽  
Gust Factor ◽  
Characteristics Analysis ◽  
Wind Characteristics ◽  
The Mean ◽  
The Relationship

The field measurement was conducted to observe the wind field data of West Pacific typhoon “Maria” in this research. With the application of ultrasonic anemometers installed in different heights (10 m, 80 m, 100 m) of the tower, the three dimensional wind speed data of typhoon “Maria” was acquired. In addition, vane-type anemometers were installed to validate the accuracy of the wind data from ultrasonic anemometers. Wind characteristics such as the mean wind profile, turbulence intensity, integral length scale, and wind spectrum are studied in detail using the collected wind data. The relationship between the gust factor and turbulence intensity was also studied and compared with the existing literature to demonstrate the characteristics of Maria. The statistical characteristics of the turbulence intensity and gust factor are presented. The corresponding conclusion remarks are expected to provide a useful reference for designing wind-resistant buildings and structures.

AN INTEGRATED APPROACH TO PREDICT OUTFLOW HYDROGRAPH DUE TO LANDSLIDE DAM FAILURE BY OVERTOPPING AND SLIDING

2008 ◽  
Vol 52 ◽  
pp. 151-156 ◽  
Author(s):  
Ripendra AWAL ◽  
Hajime NAKAGAWA ◽  
Kenji KAWAIKE ◽  
Yasuyuki BABA ◽  
Hao ZHANG
Keyword(s):  
Landslide Dam ◽  
Integrated Approach ◽  
Dam Failure ◽  
Outflow Hydrograph

scholarly journals MAKNA SIMBOLIK TOR-TO RSOMBAH DALAM UPACARA ADAT KEMATIAN SAYUR MATUA PADA MASYARAKAT SUKU BATAK SIMALUNGUN

2019 ◽  
Vol 16 (2) ◽  
pp. 219
Author(s):  
Febrina Athylata Purba ◽  
S Slamet
Keyword(s):  
Social System ◽  
Qualitative Method ◽  
Field Data ◽  
Symbolic Meaning ◽  
Hand Gestures ◽  
Field Data Collection ◽  
Symbolic Meanings ◽  
The Relationship ◽  
Musical Accompaniment ◽  
Tor Tor

<p>Penelitian yang berjudul “Makna Simbolik <em>Tor-torsombah </em>Dalam Upacara Adat Kematian <em>Sayur Matua </em>Pada Masyarakat Suku Batak Simalungun” merupakan bentuk pertunjukan tari yang terkait dalam upacara adat kematian <em>sayur matua</em>. Penelitian ini bertujuan untuk menggali makna simbolik <em>Tor-tor Sombah </em>dalam upacara adat kematian <em>sayur matua, </em>bagaimana hubungan antara <em>Tor-tor Sombah Sombah </em>dengan upacara adat kematian <em>sayur matua </em>pada masyarakat suku Batak Simalungun, serta bentuk pertunjukan <em>Tor-tor Sombah Sombah </em>dalam upacara adat kematian <em>sayur matua. </em>Permasalahan dalam penelitian ini diungkapkan dengan mendeskripsikan bentuk dari <em>Tor-tor Sombah Tor-tor Sombah </em>yang dilihat dari elemen-elemen koreografi dengan dibantu oleh notasi laban dan dianalisis dengan memakai teori dari Laban yaitu <em>effort </em>dan <em>shape</em>. Selain itu juga dalam penelitian ini bertujuan untuk menganalisis makna simbolis <em>Tor-tor Sombah </em>yang dilihat dari dua bagian yaitu aspek dalam dan aspek luar dengan konsep dari Allegra Fuller Synder. Adapun metode yang digunakan dalam pengumpulan data ini adalah metode kualitatif dengan pendekatan etnokoreologi. Teknik pengumpulan data lapangan menggunakan model dari Kurath dengan metode etnografi tari. Hasil penelitian menunjukan bahwa <em>Tor-tor Sombah Tor-tor Sombah </em>dalam upacara adat kematian <em>sayur matua </em>bagi masyarakat suku Batak Simalungun dilaksanakan sebagai penyampaian rasa hormat anak kepada orang tua yang sudah meninggal. <em>Tor-tor Sombah </em>dalam kehidupan masyarakat suku Batak Simalungun saling berkaitan dan merupakan bagian dari adat yang digerakkan secara simbolis pada upacara adat<em>. Tor-tor Sombah </em>memiliki makna dan simbol dalam unsur sajian yang ditampilkan yaitu: dalam gerak tangan, iringan musik, busana, tata rias, properti, dan <em>umpasa</em>. Gerakan pada tangan yang terdapat dalam <em>Tor-tor Sombah </em>mempunyai tiga</p><p>bentuk, yaitu :<em>sombah</em>, <em>mangalo-alo</em>, <em>mamasu-masu. </em>Selain menunjukkan bahwa <em>Tor-tor Sombah </em>memiliki makna simbolik, berkaitan juga sebagai media komunikasi, dan melalui gerak yang disajikan terjadi interaksi antar peserta upacara. <em>Tor-tor Sombah </em>menjadi bagian dari kebudayaan yang berfungsi untuk menjaga serta mempertahankan kelangsungan sistem sosialnya pada masyarakat suku Batak Simalungun.</p><p> </p><p><strong>Kata kunci: </strong><em>or-tor Sombah, </em>Upacara Adat Kematian <em>Sayur Matua </em>Batak Simalungun, Koreografi, Makna Simbolik.</p><p> </p><p><strong><em>ABSTRACT</em></strong></p><p><strong><em> </em></strong></p><p><em>The study entitled “Makna Simbolik Tor-tor Sombah Dalam Upacara Adat Kematian Sayur Matua Pada Masyarakat Suku Batak Simalungun” is a form of dance performance concerning the traditional ceremony of Sayur Matua death. This study aims to explore the symbolic meaning of Tor-tor Sombah in Sayur Matua death ceremony, how the relationship between Tor-tor Sombah and the traditional ceremony of Sayur Matua death in Batak Simalungun tribe, as well as the form of Tor-tor Sombah performance at the ceremony of Sayur Matua death. The problems in this study are expressed by describing the form of Tor-tor Sombah Tor-tor Sombah which is seen from the choreographic elements through Laban notation and is analyzed by using Laban theories, namely </em>effort <em>and </em>shape<em>. In addition, this study also aims to analyze the symbolic meaning of Tor-tor Sombah based on the inner and outer aspects with the concept of Allegra Fuller Synder. The data is collected by using qualitative method with an ethnochoreological approach. The Field data collection uses models from</em></p><p><em>Kurath through dance ethnographic methods. The results of the study show that Tor-tor Sombah in Sayur Matua death ceremony in Batak Simalungun tribe represents the delivery of children’s respect towards their deceased parents. The Tor- tor Sombah is interrelated with the life of Batak Simalungun tribe and is part of the custom that is symbolically presented in traditional ceremonies. Tor-tor Sombah has meanings and symbols in the elements of presentation, namely: hand gestures, musical accompaniment, costume, make-up, property, and </em>umpasa<em>. There are three forms of hand gestures in the Tor-tor Sombah, namely: sombah, mangalo alo, mamasu-masu. Besides the symbolic meaning contained in Tor-tor Sombah, it also represents a medium of communication. The presented movement causes an interaction among the participants of the ceremony. The Tor-tor Sombah is part of a culture that serves to maintain the continuity of its social system in Batak Simalungun tribe.</em></p><p><em> </em></p><p><strong><em>Keywords: </em></strong><em>Tor-tor Sombah, Traditional Ceremony of Sayur Matua Death of Batak Simalungun, Choreography, Symbolic Meanings.</em></p>

scholarly journals Daily Players’ Satisfaction with Pitching Performance Could Predict Shoulder and Elbow Injuries in High-school Baseball Pitchers: A Prospective Time-to-event Study

2021 ◽  
Author(s):  
Hitoshi Shitara ◽  
Tsuyoshi Tajika ◽  
Takuro Kuboi ◽  
Tsuyoshi Ichinose ◽  
Tsuyoshi Sasaki ◽  
...  
Keyword(s):  
High School ◽  
Event Study ◽  
Operating Characteristics ◽  
Time To Event ◽  
Elbow Injury ◽  
Shoulder Range Of Motion ◽  
Elbow Injuries ◽  
Characteristics Analysis ◽  
Baseball Pitchers ◽  
The Relationship

Abstract The relationship between baseball pitchers’ satisfaction with their own performance and the incidence of shoulder and elbow injuries is unclear. We analyzed the relationship between daily satisfaction scores before injury and incidence of shoulder/elbow injury in high-school baseball pitchers in this prospective, time-to-event study. We collected baseline data on baseball experience, height, weight, elbow and shoulder range of motion, and shoulder muscle strength. The 108 enrolled participants aged 15-17 years were divided into satisfied (88) and unsatisfied (22) groups based on the Receiver operating characteristics analysis results that revealed the cutoff value to be 4 points. The incidence of injury was 10.2% and 50.0% in the satisfied and unsatisfied groups, respectively. We observed that high-school baseball pitchers with a low satisfaction significantly increased the risk of shoulder and elbow injuries: these players had a 7.3-times greater risk of injuries and a 1.9-times earlier occurrence of injuries than pitchers who are satisfied with their performance. High-school baseball pitchers who had low satisfaction with their pitching performance had higher risk of shoulder and elbow injuries and lower time to injury than satisfied pitchers. Daily evaluation of players’ self-satisfaction could predict shoulder and elbow injuries in high-school baseball pitchers.

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