safety factor
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2022 ◽  
Vol 46 ◽  
pp. 103788
Jaroslav Halvonik ◽  
Jana Kalická ◽  
Lucia Majtánová ◽  
Mária Minárová

2022 ◽  
pp. 1-20
D. Xu ◽  
G. Chen

Abstract In this paper, we expolore Multi-Agent Reinforcement Learning (MARL) methods for unmanned aerial vehicle (UAV) cluster. Considering that the current UAV cluster is still in the program control stage, the fully autonomous and intelligent cooperative combat has not been realised. In order to realise the autonomous planning of the UAV cluster according to the changing environment and cooperate with each other to complete the combat goal, we propose a new MARL framework. It adopts the policy of centralised training with decentralised execution, and uses Actor-Critic network to select the execution action and then to make the corresponding evaluation. The new algorithm makes three key improvements on the basis of Multi-Agent Deep Deterministic Policy Gradient (MADDPG) algorithm. The first is to improve learning framework; it makes the calculated Q value more accurate. The second is to add collision avoidance setting, which can increase the operational safety factor. And the third is to adjust reward mechanism; it can effectively improve the cluster’s cooperative ability. Then the improved MADDPG algorithm is tested by performing two conventional combat missions. The simulation results show that the learning efficiency is obviously improved, and the operational safety factor is further increased compared with the previous algorithm.

Lafridha Alyazahari ◽  
Luthfi Amri Wicaksono ◽  
Dwi Nurtanto

A Landslide is the movement of soil mass or rock constituents down the slope due to disturbance of soil stability. One of the factors that affect soil stability is the rainy season as happened in Sumberwuluh Village, Candipuro District, Lumajang Regency. The alternative used to stabilize the slope is by changing the slope geometry, then adding geoframe reinforcement. This study aims to determine the value of the factor of safety (SF) of unreinforced slopes, after changing the slope geometry, and after being given geoframe reinforcement. The method used in analyzing slope stability is the Ordinary/Fellenius method. The results of the calculation of slope stability without reinforcement using the Rocscience Slide software obtained a SF of 0.719, while the manual calculation obtained a SF of 0.7191. The two values ​​of the safety factor are less than 1.25, which means that landslides often occur. The results of the calculation of slope stability after changing the geometry of the slopes obtained a SF of 0.828 where the value is less than 1.25 which means that landslides often occur. The slopes that have been changed geometry are added with geoframe reinforcement. The results of the calculation of slope stability using geoframe reinforcement obtained a SF of 1.315 where the value is more than 1.25 which means that landslides are rare or slope in a safe condition.

2022 ◽  
Vol 9 ◽  
Qingqing Zhang ◽  
Laigui Wang ◽  
Huabin Zhang

In order to analyze the effects of rainfall events on the stability of an open-pit rock slope, with considering the spatial variability of saturated hydraulic conductivity, based on the unsaturated seepage theory and the random filed theory, modified functions of the unit saturation, the hydraulic conductivity (k), and the shear strength parameters are established for unsaturated slope, by using FISH and the non-intrusive stochastic method. A saturated-unsaturated seepage random field model is proposed. And then the impacts of the rainfall intensity, the rainfall duration, and the spatial variability of saturated hydraulic conductivity (ks) on the infiltration process and stability of the unsaturated rock slope are analyzed. The results show that the proposed model can estimate rainfall infiltration of rock slope accurately. Rainfall mainly affects the seepage field in the shallow layer of the slope, where a transient saturated zone can be formed. With the development of the rainfall duration, the weight of the rock mass increased, the matric suction reduced, the negative pore pressure, the degree of saturation, and the infiltration depth of the rock slope increased, and the water in the slope root connects with the initial water table gradually, the unsaturated zone shrinks, which causes the safety factor of the model decreases, but the trend of change slows down gradually. As the rainfall intensity strengthened, the infiltration depth increased and the safety factor of the slope reduced, while the changing rate increases first and then decreases. Increasing the correlation length of k can reduces the infiltration depth and safety factor of the slope. Increasing the variation coefficient of k will increase the infiltration depth, while the safety factor of the slope decreases. The infiltration depth and safety factor of the slope are most affected by rainfall duration, but its sensitivity to the variability coefficient of k will be strengthened when the rainfall intensity exceeds the infiltration capacity. This conclusion can provide reference significance for the risk estimation of slope geological hazards, which are induced by the rainfall infiltration.

2021 ◽  
Vol 5 (3) ◽  
pp. 307-316
Dewi Amalia ◽  
Bagus Guritno ◽  
Geni Firuliadhim

Many studies have begun to develop the concept of cracked soil. The results of research related to cracked soil are able to answer the irregularities that occur, such as the difference in the results of the stability analysis which is considered safe with the conventional bishop method, while the conditions in the field are landslides. Swelling soil is soil that is susceptible to changes in water content. This type of soil is very prone to cracking. To build infrastructure on the swelling soil type, an improvement must be made, one of which is by mixing the swelling soil with biopolymer. The results of this biopolymer mixing are then modeled in the New Slope Stability Analysis Program (NSSAP) 1.0 which refers to the concept of cracked soil. From the analysis, it was found that the slope safety factor before improvement with biopolymer was 0.305 and the safety factor after improvement with biopolymer was 2.006. From the results of this study, it can be seen that the role of biopolymers in stabilizing swelling soil is quite large, which is around 558%.

S. N. Popov ◽  

The results of laboratory studies of the elastic-strength properties of cement stone samples depending on the hardening time and the effect of an acid reagent, and approximated dependences of the change in the elastic modulus, Poisson's ratio and strength properties, depending on the time characteristics for two types of plugging materials are presented. A finite element scheme of the nearwellbore zone has been developed, taking into account the cement stone and the production casing. The results of numerical modeling of the stress-strain state of columns with a diameter of 146 and 178 mm, cement stone and reservoir rocks near the well based on an elastic model are presented. The analysis of the stress field for the occurrence of zones of destruction in the cement stone using the Coulomb-Mohr criterion is carried out. It is shown that, depending on the time of hardening and the effect of an acidic reagent, cement does not collapse and retains a sufficient safety factor. Keywords: cement stone; plugging material; elastic-strength properties; near-wellbore zone; numerical model; finite element method; stress-strain state; safety factor.

Technologic ◽  
2021 ◽  
Vol 12 (2) ◽  
Reinata Avhycanti Laventina ◽  
Kartika Setiawati

Jalan Tol Trans Sumatera Pekanbaru-Dumai merupakan ruas jalan tol utama karena digunakan untuk mobilisasi dan bisnis kota Pekanbaru-Dumai. Timbunan pada badan Jalan Tol Trans Sumatera merupakan faktor penting untuk struktur geoteknik di sekitar lereng yang berada di badan jalan tol. Timbunan tanah pada badan jalan tol digunakan untuk pencapaian elevasi akhir subgrade tanah. Pengaruh analisis stabilitas lereng serta penurunan konsolidasi tanah sangat berpengaruh pada analisis struktur geoteknik untuk timbunan tanah. Permasalahan yang terjadi adalah terjadi penurunan yang disertai kelongsoran sebagian lebar badan jalan di STA 79+ 615. Jalan Tol Trans Sumatera Seksi V Pekanbaru-Dumai dan box culvert tanah dasar mengalami penurunan. Kerusakan yang terjadi pada kedua lokasi berupa penurunan disertai retakan arah jalan dengan pergeseran tanah kearah samping (longsor). Analisis terhadap sisi geoteknik menggunakan perkuatan salah satunya menggunakan struktur pile embankment. Pada analisis perkuatan dan penanganan timbunan menggunakan struktur pile embankment akan dilakukan analisis faktor keamanan timbunan jalan. Parameter perkuatan dan penanganan timbunan tanah (sudut geser dalam, poisson ratio, kohesi, modulus elastisitas, dan muka air tanah) dapat digunakan untuk analisis struktur geoteknik berikutnya. Analisis perkuatan akan menggunakan aplikasi Plaxis (program analisis geoteknik dengan basis finite element method). Direncanakan untuk pile embankment dengan tipe spun pile dapat mencapai nilai safety factor 1,5 (faktor keamanan terhadap stabilitas global minimum SNI 8460-2017) dan mencapai nilai safety factor 1,1 (faktor keamanan terhadap beban gempa SNI 8460-2017) dengan dimensi spun pile diameter 60 cm, panjang efektif 10-12 meter dengan jarak spasi antar spun pile adalah 3 meter, dan tebal LTP (Load Transfer Platform) sebesar 1,8 meter.

UKaRsT ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 236
Akhmudiyanto Akhmudiyanto ◽  
Paulus Pramono Rahardjo ◽  
Rinda Karlinasari

One of the causes of on-road collapse slopes is traffic load. Slope failure by road loads usually occurs due to several factors such as soil type, rainfall, land use. This study aims to determine landslide and slope repair performance using bore pile and ground anchor on Cipali Toll Road KM 103. The research method used in this study is the Finite element method. In this research, data collection, modeling parameter determination, slope stability analysis, slope reinforcement analysis, and reinforcement design were carried out with variations in bore pile and ground anchor dimensions. The software program used is a finite element program in the form of PLAXIS to analyze slope stability and estimate the slope failure area. The result of the study is that the R-Value inter is 0.25 with a 1.0341 safety factor. Best repair performance obtained from the addition of reinforcement with ground anchor 2 layer on bore pile 2 with a distance of 2 meters increased the safety factor to 1,913; Borepile capacity calculation with the calculation of normal force and moment iteration, the largest occurs in the DPT (Retaining Wall) stage with a normal load of -37.9 and a moment force of -471.15 which is still able to be borne by bore pile 1. The result of this study is expected to be benchmark and repair material to improve slope stability at km 103 Tol Cipali

Xiao-Gang Wang ◽  
Xin-Chao Lin

In this paper, an optimized solution method is proposed for the 3D stability analysis of rock slopes subject to toppling failure based on their geometric and mechanical properties. It was verified by a 3D block system that focused on the geometric properties of toppling slopes as a research object, considering the force and its action point on the interface of the block system as unknown variables, as well as introducing the definition of a safety factor considering both tension and shear strength reduction. The proposed method implied setting constraints, such as the balance equation corresponding to block force and moment, as well as non-violation of the yield criterion, considering the minimum value of the safety factor as the objective function. It was applied to the analysis of two typical 3D models simulating toppling failure on slopes. The example of a 3D spherical toppling slope was reconstructed and corroborated by calculations. The experimental results demonstrated that the proposed method could appropriately reflect the mechanical properties and stability behavior of a 3D toppling slope, thereby facilitating the analysis of the stability of 3D toppling rock slope model.

2021 ◽  
Vol 10 (2) ◽  
pp. 41-53
Ardha Rahadian1 ◽  
Lalu Mulyadi ◽  
Lies K. Wulandari

A highway toll project is an urgent need in this modernization era, especially in our country, which currently has a population of around 250 million people. From the population that has been increasing, In the current era the need for transportation is also growing rapidly, Therefore, a safe and comfortable transportation is needed. Relationship with the occurred of soft soil in the STA. 18 + 000 to STA. 20 + 300, the authors need to provide an analyzing way of handling the soft soil in order to meet the criteria for the settlement criteria. Meanwhile, the purpose of making analysis soft soil improvement using minipile is to find out a technical point still meets the requirements stated in the design criteria. To achieve this goal, analysis of the soft soil improvement in carrying out the analysis and calculations was taken from the results analysis of the N-SPT value and laboratory testing material from the soil investigation of the borehole. The calculation results obtained are in the soil improvement methods at the location which was originally using a minipile it can reduce settlement value < 20 mm/years, safety factor in earthquake condition > 1.10 and time schedule for implementation pilling work on site 1 month faster than the time required when using another methods for each location that has of soft soil content, especially in the section STA. 18 + 000 to STA. 20 + 300.

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