scholarly journals Evaluation of the Groundsill’s stability at downstream of “Citorek” Bridge in Cimadur River, Banten Province

2021 ◽  
Vol 880 (1) ◽  
pp. 012029
Author(s):  
Arniza Fitri ◽  
Hao Chen ◽  
Li Yao ◽  
Ke-hong Zheng ◽  
Susarman ◽  
...  
Keyword(s):  
Water Level ◽  
Safety Factors ◽  
Bridge Abutments ◽  
Specific Design ◽  
Period 2 ◽  
Optimal Function ◽  
Normal Water ◽  
Local Water ◽  
The Stability ◽  
Topography Data

Abstract Scouring problems faced in the Cimadur River especially near to the Citorek bridge abutments have become the major discussion by the local researchers and the local water resources manager in Banten Province. As an effort in reducing the scouring problem around the abutment of the Citorek bridge, a groundsill structure with specific design is going to be installed in Cimadur River at downstream of Citorek bridge. To make sure the optimal function of the structure, the stability of the groundsill structure in Cimadur River need to be evaluated. This study attempt to evaluate the stability of a groundsill structure from the occurrences of rolling and sliding at both normal and flood conditions. The eccentricity of the groundsill structure is also checked during normal and flood conditions to make sure the stability of the structure. The required data (which are consisting of detail description of the groundsill structure, cross section of the river, rainfall data, topography data and sediment/soil data) are observed in the field and obtained from P.T. Saeba Konsulindo. The data are further analysed to determine: 1) design water discharges for several return period, 2) forces acting to the groundsill structure and 3) stability of the groundsill structure in the river. The results showed that the groundsill structure are stable and safety again rolling and sliding occurrences where the safety factor (SF) for rolling and sliding are higher than critical coefficients of rolling and sliding (1.5). At normal water level, safety factors (SF) for rolling and sliding are 8.07>1.5 and 2.7>1.5, respectively, while at flood water level, SF for rolling and sliding are 5.61>1.5 and 1.88>1.5, respectively. Besides, the results also found that the groundsill is safety from eccentricity at both normal and flood conditions where the calculated coefficients of eccentricities are lower than critical coefficient of eccentricity which could cause rolling and sliding.

scholarly journals Analisis Stabilitas Lereng Menggunakan Model Numerik 3 Dimensi Studi Kasus Lereng Sekolah Terpadu di Kecamatan Jonggol Bogor

2020 ◽  
Vol 3 (2) ◽  
pp. 54
Author(s):  
Desti Santi Pratiwi ◽  
Nirpan Lesmana ◽  
Indra Noer Hamdhan
Keyword(s):  
Water Level ◽  
Drainage System ◽  
Water Levels ◽  
3 Dimensional ◽  
Bored Pile ◽  
Normal Water ◽  
Bored Piles ◽  
The Stability ◽  
Steep Slopes

<p class="BodyAbstract">Slope is the surface of the earth that forms an inclination angle, that it has the potential for landslides. Landslide will be occurred by several factors, such as steep slopes, large loads, high rain intensity, poor drainage systems, high ground water levels and others. Therefore, slope stability analysis is needed to ensured that the slopes are safe from landslides potential which injured many people. As for the prevention and handling of landslides that can be done, such as changing the geometry of the slopes, improving the drainage system, providing slope reinforcement such as gabions, retaining walls, poles and others. This study aims to determine the effect of water level on the stability of the existing slope and which has been reinforced by bored piles using a 3-dimensional numerical model. The case study reviewed is the slope in the Integrated School in Bendungan Village, Jonggol District, Bogor Regency. The results of the analysis show that in the existing conditions with a normal water level, the value of the safety factor (SF) is 1.16, and when the water level is critical, the SF value is 1.14. Whereas in slope conditions with the reinforcement of the bored pile, the analysis results show that the SF value with normal water level is 2.33 and when the water level is critical is 1.58. The results of the analysis with the reinforcement of the drill pile show that the SF value is more than 1.5 so that the slope is safe from landslide based on SNI 8460 of 2017.</p>

scholarly journals EVALUASI STABILITAS DINDING PENAHAN TANAH TIPE KANTILEVER DI DESA NGROTO, KECAMATAN PUJON, KABUPATEN MALANG

2021 ◽  
Vol 15 (1) ◽  
pp. 22
Author(s):  
Suhudi Suhudi ◽  
Simplisius Ehok
Keyword(s):  
Bearing Capacity ◽  
Water Level ◽  
Safety Factor ◽  
Shear Force ◽  
Rainfall Intensity ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Total Cost ◽  
Normal Water ◽  
The Stability

AbstractWavy topographical conditions with high rainfall intensity cause cantilever type retaining wall on Jalan Brigjen Abdul Manan Wijaya in Ngroto village, Pujon District, Malang Regency, which borders the Konto River avalanche. The stability of the retaining wall can be expressed as Fs (Savety Factor). Factor value the security that is reviewed is the Fs bolster, namely the safety factor against the overthrowing force, the Fs shear is the safety factor against the shear force at the base of the retaining wall, Fs, the bearing capacity of the soil is a factor safety of soil bearing capacity. The purpose of this evaluation is to determine the wall planning cantilever type retaining wall and evaluate the stability of cantilever type retaining wall against the dangers of rolling, shearing, soil bearing capacity and knowing the budget plan for wall planning Cantilever type retaining wall. The result of this evaluation shows the cantilever retaining wall with dimensions H = 7, B = 3.5 Ta = 0.5 Tb = 0.7 D = 1 declared safe with the safety value for normal water level fs slide 1.8> 1.5 (safe), fs roll 2> 1.5 (safe), fs ground bearing capacity 186.8> 4752.86 (safe). Water face flood fs shear 2,6> 1,5 (safe) fs rolling 2,3> 1,5 (safe) fs soil bearing capacity 186.8> 4752.86 (safe). The total cost required for the construction of a cantilever type retaining wall of length 20 m T = 7 width 3.5 m for Rp. 290,570,000.Keywords: Retaining walls, Dimensions, Stability of retaining walls

Nonstationary Response of a Two-Degrees-of-Freedom Nonlinear Ship Model Under Modulated Excitation

1995 ◽  
Author(s):  
Ruigui Pan ◽  
Huw G. Davies
Keyword(s):  
Degrees Of Freedom ◽  
Stability Boundary ◽  
Period Doubling ◽  
Approximate Solutions ◽  
Loss Of Stability ◽  
Two Degrees Of Freedom ◽  
Ship Model ◽  
Nonstationary Response ◽  
Period 2 ◽  
The Stability

Abstract Nonstationary response of a two-degrees-of-freedom system with quadratic coupling under a time varying modulated amplitude sinusoidal excitation is studied. The nonlinearly coupled pitch and roll ship model is based on Nayfeh, Mook and Marshall’s work for the case of stationary excitation. The ship model has a 2:1 internal resonance and is excited near the resonance of the pitch mode. The modulated excitation (F0 + F1 cos ωt) cosQt is used to model a narrow band sea-wave excitation. The response demonstrates a variety of bifurcations, loss of stability, and chaos phenomena that are not present in the stationary case. We consider here the periodically modulated response. Chaotic response of the system is discussed in a separate paper. Several approximate solutions, under both small and large modulating amplitudes F1, are obtained and compared with the exact one. The stability of an exact solution with one mode having zero amplitude is studied. Loss of stability in this case involves either a rapid transition from one of two stable (in the stationary sense) branches to another, or a period doubling bifurcation. From Floquet theory, various stability boundary diagrams are obtained in F1 and F0 parameter space which can be used to predict the various transition phenomena and the period-2 bifurcations. The study shows that both the modulation parameters F1 and ω (the modulating frequency) have great effect on the stability boundaries. Because of the modulation, the stable area is greatly expanded, and the stationary bifurcation point can be exceeded without loss of stability. Decreasing ω can make the stability boundary very complicated. For very small ω the response can make periodic transitions between the two (pseudo) stable solutions.

scholarly journals Low back pain in physiotherapy students: Prevalence and the association with neuromuscular findings

2013 ◽  
Vol 69 (4) ◽  
Author(s):  
E. Burger ◽  
H. Myezwa ◽  
V. Naidoo ◽  
B. Olivier ◽  
A. Rothberg
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Cross Sectional Study ◽  
Transversus Abdominis ◽  
Low Back ◽  
Cross Sectional ◽  
Active Involvement ◽  
Optimal Function ◽  
The Stability ◽  
Physiotherapy Students

Background: Physiotherapy students are prone to low back pain (LBP) due to studying and their active involvement in clinical treatment of patients. As a result of pathology, muscle activity is influenced, affecting optimal function of the spine. Method: Physiotherapy students enrolled for 2010 at the University of the Witwatersrand participated in a cross-sectional study. A questionnaire and physical assessment were completed. Results: The study revealed that the lifetime LBP prevalence was 36% among physiotherapy students. Associations with LBP were hours of practical exposure, posterior-anterior mobilisations on L4 (p=0.003) and L5 (p≤0.001) centrally and unilaterally, left lumbar multifidus (LM) cross-sectional area (p=0.02), right obliquus internusabdominis (OI) (p=0.02) and right transversus abdominis (TrA) thickness at rest (p=0.02), as well as the pull of the TrA during contraction on the left (p=0.03). Discussion: Hours of practical exposure may play a role in lumbar pathology. Due to pathology, muscle imbalances of LM, TrA and OI affect the stability of the spine which may lead to recurrences. Conclusion: Practical exposure as well as LM, TrA and OI muscle imbalances were associated with LBP in physiotherapy students. Awareness of the factors associated with LBP while studying at an undergraduate level may lead to better prevention of LBP.

scholarly journals Unsteady Seepage Behavior of an Earthfill Dam During Drought-Flood Cycles

Geosciences ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 17 ◽  
Author(s):  
Ziyang Li ◽  
Wei Ye ◽  
Miroslav Marence ◽  
Jeremy Bricker
Keyword(s):  
Pressure Gradient ◽  
Water Level ◽  
Pore Pressure ◽  
Internal Erosion ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Upstream Slope ◽  
Earthfill Dams ◽  
The Stability ◽  
Pore Pressure Gradient

Climate change with extreme hydrological conditions, such as drought and flood, bring new challenges to seepage behavior and the stability of earthfill dams. Taking a drought-stricken earthfill dam of China as an example, the influence of drought-flood cycles on dam seepage behavior is analyzed. This paper includes a clay sample laboratory experiment and an unsteady finite element method seepage simulation of the mentioned dam. Results show that severe drought causes cracks on the surface of the clay soil sample. Long-term drought causes deeper cracks and induces a sharp increase of suction pressure, indicating that the cracks would become channels for rain infiltration into the dam during subsequent rainfall, increasing the potential for internal erosion and decreasing dam stability. Measures to prevent infiltration on the dam slope surface are investigated, for the prevention of deep crack formation during long lasting droughts. Unsteady seepage indicators including instantaneous phreatic lines, equipotential lines and pore pressure gradient in the dam, are calculated and analyzed under two assumed conditions with different reservoir water level fluctuations. Results show that when the water level changes rapidly, the phreatic line is curved and constantly changing. As water level rises, equipotential lines shift upstream, and the pore pressure gradient in the dam’s main body is larger than that of steady seepage. Furthermore, the faster the water level rises, the larger the pore pressure gradient is. This may cause internal erosion. Furthermore, the case of a cracked upstream slope is modelled via an equivalent permeability coefficient, which shows that the pore pressure gradient in the zone beneath the cracks increases by 5.9% at the maximum water level; this could exacerbate internal erosion. In addition, results are in agreement with prior literature that rapid drawdown of the reservoir water level is detrimental to the stability of the upstream slope based on embankment slope stability as calculated by the Simplified Bishop Method. It is concluded that fluctuations of reservoir water level should be strictly controlled during drought-flood cycles; both the drawdown rate and the fill rate must be regulated to avoid the internal erosion of earthfill dams.

scholarly journals ANALISIS KEAMANAN LERENG BENDUNGAN UTAMA PADA BENDUNGAN BENEL DI KABUPATEN JEMBRANA

1970 ◽  
Author(s):  
I G. N. Putu Dharmayasa ◽  
I W. Redana ◽  
Tjok Gde Suwarsa Putra
Keyword(s):  
Water Level ◽  
Safety Factor ◽  
The Body ◽  
Security Requirements ◽  
Seismic Load ◽  
Dam Safety ◽  
Seepage Discharge ◽  
Minimum Requirement ◽  
Downstream Slope ◽  
Normal Water

Development of dam very important for community surrounding the dam. To maintain that the benefits can be continued, it is necessary to review whether the safety of dams already meet the expected requirements. Dam safety to be reviewed when the dam was built and when the dam operating at this time. Security conditions associated with changes in water level on the upstream dam that affects the seepage on the body of dam and seepage under the dam. The water level also affects the slope of the dam when the dam has been operating.  Evaluation of the safety of the dam was conducted on Benel dam which located in Melaya District, Jembrana Regency, Bali Province. The results of the calculation of seepage (q) in the dam body with SEEP/W and flownet shows that, seepage discharge (q) which passes through under the dam and the body of dam is less than 1% (4.9206 m3/second) against the average flood discharge, so it has met the security requirements. Dam safety factor calculations without seismic load and with seismic load, for upstream slope and downstream slope when the dam was constructed,  when operating with flood water level,  when operating in the rainy season (normal water level),  when operating in the dry season (minimum water level) and with rapid draw down condition, with SLOPE/W and the Bishop method, the safety factor obtained more than minimum requirement by RSNI M-03-2002.

scholarly journals Modelling the Impacts of Bathymetric Changes on Water Level in China’s Largest Freshwater Lake

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1469 ◽  
Author(s):  
Lingyan Qi ◽  
Jiacong Huang ◽  
Junfeng Gao ◽  
Zhen Cui
Keyword(s):  
Water Level ◽  
Water Resource Management ◽  
Freshwater Lake ◽  
Lake Ecosystem ◽  
Spatial Gradient ◽  
Dramatic Decline ◽  
Hydrodynamic Processes ◽  
Lake Poyang ◽  
The Stability ◽  
Bathymetric Changes

A recent dramatic decline in water level during the dry season in China’s largest freshwater lake (Lake Poyang) significantly influenced water availability and biogeochemical processes. To learn the potential causes of water level decline, this study investigated the hydrodynamic response to bathymetric changes during three typical hydrological years by scenario simulation using Environmental Fluid Dynamics Code (EFDC). The simulation results indicated that bathymetric changes resulted in a water level decrease during a low water level period. Inter-annual variation in the decrease rate implied that water level in typical dry and wet years were influenced more significantly than that in moderate hydrological years. A spatial gradient in the distribution of water level changes was also observed, which was mainly concentrated in the main channel. Water velocities also slowed down, weakly corresponding to the decrease in water level during the low water level period. Overall, bathymetric changes caused by sand mining contributed to water level and velocity variations, influencing the stability and sustainability of the lake ecosystem. This study can potentially enhance our understanding of the hydrodynamic processes in Lake Poyang and support water resource management.

Overburden Rock Stability Analysis of Shallow Tunnel

2011 ◽  
Vol 105-107 ◽  
pp. 1304-1307
Author(s):  
Yun Long Wang ◽  
Zhong Sheng Tan
Keyword(s):  
Jiaozhou Bay ◽  
Decisive Role ◽  
Overburden Rock ◽  
Safety Factors ◽  
Tunnel Stability ◽  
Rock Stability ◽  
Subsea Tunnel ◽  
The Stability ◽  
The Moment ◽  
Elastic Foundation Beam

As for shallow tunnels through the rock layers, the stability of the overburden rock has a decisive role on the tunnel stability; furthermore, analyzing the stability of the overburden rock is very important to the supporting design and the choice of excavation method. Method of elastic foundation beam is used to research the moment of overburden rock, and the formula of overburden rock stable thickness is finished. Seven sections of JIAOZHOU Bay Subsea Tunnel are took for example to analyze the safety factor of different span and overburden rock thickness, then the stability of overburden rock is analyzed. The results show that the overburden rock safety factors of these seven sections of JIAOZHOU Bay Subsea Tunnel are range from 0.65 to 0.85. Compared with the experimental results, theoretical analysis of the results are more consistent The actual example verifies that the overburden rock stability in this paper is feasible.

Sign in / Sign up

Export Citation Format

Share Document