Mechanics Analysis of Grade V Surrounding Rock Primary Support in Maanziliang Tunnel

Highway Tunnel ◽

Geological Conditions ◽

The Stability ◽

Primary Support ◽

Rock Section

Commonly used finite element strength reduction to calculate the safety factor of slope，to analyze the stability of the slope[1～3]. Recently it also proposed the methods to evaluate the safety factor for the stability of surrounding rock of underground chambers and supporting structural mechanics[4～6]. For Qinling Mountains of the complex geological conditions in the Maanziliang highway tunnel, this article use the finite element method from the bolt resist tension, bolt length, the force of sprayed layer of concrete to computing gradeⅤsurrounding rock section of primary support safety factor, to give evaluation to support mechanics of the Maanziliang tunnel.

Analysis of Seepage Field of Highway Tunnel Excavation by Finite Difference Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.798 ◽

2014 ◽

Vol 638-640 ◽

pp. 798-803

Author(s):

Yong Tao Zhang

Keyword(s):

Finite Difference ◽

Circulatory System ◽

Surrounding Rock ◽

Design Parameters ◽

Seepage Field ◽

Tunnel Excavation ◽

Highway Tunnel ◽

Geological Conditions ◽

Fracture Development ◽

As the excavation of tunnels, there are new channels of the groundwater drainage. The original supply of the circulatory system has been destroyed. The effects of groundwater to rock mass of surrounding rock are aggravated. In this paper, combined with a new highway tunnel project, the model is built according to the design parameters and the site engineering geological conditions of the tunnel. The fluid-structure interaction module of the finite difference software FLAC3D is used for the research on tunnel excavation. The distribution of seepage field, the stability of surrounding rock and rock deformation under saturated conditions during the tunnel excavation have been analyzed. The simulation results have certain guiding meaning on fracture development, the stability design of tunnels in water-rich stratum and the design and construction of anti-drainage.

The Research on Application of Strength Reduction Finite Element Method in Stability Analysis of Weak Intercalated Rock Tunnel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.255-260.1926 ◽

2011 ◽

Vol 255-260 ◽

pp. 1926-1929

Author(s):

Da Kun Shi ◽

Yang Song Zhang

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Rock Mass ◽

Safety Factor ◽

Slip Surface ◽

Strength Reduction ◽

Surrounding Rock ◽

Stability Of Surrounding Rock ◽

The Stability ◽

Element Method

Based on geologic condition of one tunnel surrounding rock mass, systematic numerical tests had been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock by the FEM software ABAQUS and strength reduction finite element method. Some quantificational results about the stability of surrounding rock mass were summarized. And the safety factor and latent slip surface were worked out. The stability of surrounding rock mass was judged by strength reduction finite element method. According to the analysis above, it’s known that the discrepancy of two rules is small; the safety factor is the lowest when weak intercalated rock in vault, and when at bottom, it’s higher than that of in vault. The conclusion can be used to guide the procedure of construction and ensure the safety.

The Tunnel of Small Interval Clip Rock Mechanics Properties Research

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.170-173.1816 ◽

2012 ◽

Vol 170-173 ◽

pp. 1816-1819

Author(s):

Ye Min Zhang ◽

Wen Jian Li ◽

Jin Cai Li

Keyword(s):

Surrounding Rock ◽

Weak Rock ◽

Small Interval ◽

Element Analysis ◽

Highway Tunnel ◽

Geological Conditions ◽

Before And After ◽

Parallel Tunnel ◽

The Stability ◽

Rock Tunnel

Abstract. In jiangxi red XiaShan highway tunnel interval for engineering background, the key research different scheme for tunnel construction process between them the mechanical behavior of rock and analyzed. For small interval double hole parallel tunnel between them the complex rock stress state, the finite element analysis software for using the numerical analysis method is buried deep in the condition of small interval period of bias by different construction scheme of tunnel numerical simulation. To meshshotcreting firstly method, CD method, up and down steps method, the construction method of different displacement and deformation of the stability of surrounding rock and the comparative analysis. Analyze the different schemes of before and after the surrounding rock tunnel excavation and supporting structure composed of each other of the unity displacement change rule. Put forward the tunnel between them weak rock the concept, more explicit the engineering geological conditions of weak rock tunnel clip to control surfaces. And on the basis of guidance for engineering construction, in actual construction which has obtained a better effect. The result is of a similar project design and construction to provide the reference and the model.

Analytical and experimental research on stability of large slenderness ratio horizontal hydraulic hoist

Advances in Mechanical Engineering ◽

10.1177/1687814018803472 ◽

2018 ◽

Vol 10 (10) ◽

pp. 168781401880347 ◽

Cited By ~ 1

Author(s):

Ji Zhou ◽

Duan-Wei Shi ◽

Zhi-Lin Sun ◽

Tao Bi ◽

Xiong-Hao Cheng ◽

...

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Safety Factor ◽

Slenderness Ratio ◽

Hydraulic Cylinder ◽

Ratio Test ◽

Sliding Bearing ◽

The Stability ◽

Element Method

Taking the hydraulic cylinder for the miter gate in Dateng Gorges Water Conservancy Project as the object, a large slenderness ratio test hydraulic cylinder was designed based on the similarity theory. The buckling analysis of the test hydraulic cylinder was carried out by the finite element method, considering the friction at the supports, the misalignments between piston rod and cylinder tube, and gravity. The results indicate that the stability safety factor is 10.55. A buckling experimental system was established, and the buckling stability of the test hydraulic cylinder was tested for the sliding bearing support and the rolling bearing support at the piston-rod end, respectively. The stability safety factor is over 9.01 and 6.82 relevantly. The similarities and differences among the results of the finite element method, experimental method, NB/T 35020-2013, and two-sections pressure bar method were analyzed. Experimental and analytical results clearly show that the friction at the supports is a key factor in determining the magnitude of the stability safety for large slenderness ratio horizontal hydraulic hoist and utilizing the sliding bearing can effectively improve the stability safety factor.

ANALISA STABILITAS LERENG DAN ALTERNATIF PERKUATAN TANAH PADA JALUR KERETA API CEPAT JAKARTA-BANDUNG MENGGUNAKAN APLIKASI PLAXIS 8.6

BANGUNAN ◽

10.17977/um071v26i12021p29-44 ◽

2021 ◽

Vol 26 (1) ◽

pp. 29

Author(s):

Ainun Nafis ◽

Eko Setyawan ◽

Mohammad Musthofa Al Mohammad Musthofa

Keyword(s):

Finite Element ◽

Safety Factor ◽

High Speed ◽

Earthquake Dynamics ◽

High Speed Rail ◽

Alternative Reinforcement ◽

Embankment Slope ◽

Geological Conditions ◽

Rail Line ◽

Abstrak: Masalah dalam perencanaan struktur jalan kereta seperti tinggi lereng embankment yang lebih dari sama dengan 6 m, tanah asli yang tergolong sedang lunak, dan merupakan daerah rawan terjadinya longsor merupakan alasan dilakukannya penelitian ini. Hal tersebut didukung oleh hasil uji lab tanah, kondisi geografis dan geologis Kabupaten Purwakarta berupa bukit dan lembah yang terbentuk dari endapan batuan sedimen dan aluvium vulkanik dengan kemiringan lahan 8-40%. Oleh karena itu penelitian ini bertujuan untuk mengetahui stabilitas lereng embankment berupa nilai safety factor pada jalur kereta cepat Jakarta-Bandung daerah konstruksi DK70+150.00 sampai DK70+181.88. Adapun analisis numerik yang dilakukan pada penelitian ini menggunakan program Plaxis 8.6 yang dikembangkan berdasarkan metode Finite Element dengan model Mohr-Coulomb. Proses analisis dengan menginput parameter material yang dibutuhkan berdasarkan Mohr-Coulomb. Hasil analisis berupa angka safety factor yang menunjukkan kondisi stabilitas suatu lereng embankment. Penambahan alternatif perkuatan lereng embankment berupa cerucuk (micropile), bronjong (gabion) dan geotextile sebagai upaya pencegahan adanya kelongsoran jangka pendek dan panjang pada lereng embankment yang tidak stabil. Hasil analisis lereng embankment kereta api cepat Jakarta-Bandung DK70+150 sampai DK70+181.88 kondisi eksisting sebesar ΣMSF 1,1565 (cek global) dan ΣMSF 1,0515 (cek dinamik gempa) yang artinya lereng dalam kondisi tidak stabil dan perlu penambahan alternatif perkuatan. Berdasarkan simulasi kombinasi alternatif perkuatan. Menunjukkan kombinasi alternatif perkuatan geotextile dengan micropile menghasilkan angka safety factor ΣMSF 1,8151 (cek stabilitas global) dan ΣMSF 1,6262 (cek stabilitas akibat beban dinamik gempa).Kata-kata kunci: stabilitas lereng embankment, Plaxis 8.6, safety factor, kereta cepat Jakarta-BandungAbstract: Problems in the design of the railway structure such as the embankment slope height of 6 m, the original soil which is classified as moderately soft, and is an area prone to landslides is the reason for conducting this research. This is supported by the results of soil lab tests, geographical and geological conditions of Purwakarta Regency in the form of hills and valleys formed from sedimentary rock deposits and volcanic alluvium with a slope of 8-40%. Therefore, this study aims to determine the stability of the embankment slope in the form of the safety factor value on the Jakarta-Bandung high-speed rail line in the construction area DK70+150.00 to DK70+181.88. The numerical analysis carried out in this study used the Plaxis 8.6 program which was developed based on the Finite Element method with the Mohr-Coulomb model. The analysis process by inputting the required material parameters based on Mohr-Coulomb. The results of the analysis are in the form of safety factor numbers which indicate the stability condition of an embankment slope. The addition of alternative reinforcement for embankment slopes in the form of micropile, gabion (gabion) and geotextile as an effort to prevent short and long term landslides on unstable embankment slopes. The results of the slope analysis of the Jakarta-Bandung high-speed rail embankment DK70+150 to DK70+181.88 existing conditions of MSF: 1.1565 (global check) and MSF: 1.0515 (earthquake dynamics check) which means the slope is in an unstable condition and needs additional alternative reinforcement. Based on the simulation of alternative reinforcement combinations. Showing the alternative combination of geotextile reinforcement with micropile produces a safety factor number MSF: 1.8151 (check global stability) and MSF: 1.6262 (check stability due to dynamic earthquake loads)..Keywords: embankment slope stability, Plaxis 8.6, safety factor, Jakarta-Bandung high-speed train

Seismic Stability of Loess Tunnel with Rainfall Seepage

Advances in Civil Engineering ◽

10.1155/2020/8147950 ◽

2020 ◽

Vol 2020 ◽

pp. 1-16

Author(s):

Xuansheng Cheng ◽

Wanlin Zhang ◽

Jing Fan ◽

Xiaoyan Zhang ◽

Haibo Liu ◽

...

Keyword(s):

Finite Element ◽

Safety Factor ◽

Calculation Model ◽

Seismic Stability ◽

Infiltration Depth ◽

Seepage Theory ◽

The Stability ◽

Cover Thickness ◽

Rainfall Seepage

Rainfall seepage changes the mechanical properties of loess masses. Considering fluid-solid coupling, the calculation model of a loess tunnel is established according to the finite element method (FEM). Based on porous media seepage theory and rainfall infiltration depth theory and considering the infiltrated depth of the loess surface for different rainfall intensities over a certain period, the stability of a loess tunnel under different rainfall amounts and loess cover thicknesses is studied using the dynamic finite element static strength reduction method. The results show that under the same rainfall intensity, the safety factor increases with the depth of the tunnel; the safety factor of the loess tunnel with the same loess cover thickness decreases with increasing infiltration depth. The plastic strain is mainly distributed on both sides of the vault and the arch feet. The stability of the loess tunnel is directly related to the loess cover thickness and rainfall seepage.

Determining the Critical Slip Surface of Three-Dimensional Soil Slopes from the Stress Fields Solved Using the Finite Element Method

Mathematical Problems in Engineering ◽

10.1155/2016/7895615 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Yu-chuan Yang ◽

Hui-ge Xing ◽

Xing-guo Yang ◽

Jia-wen Zhou

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Stability Analysis ◽

Safety Factor ◽

Slip Surface ◽

Three Dimensional ◽

Soil Slope ◽

Critical Slip Surface ◽

The slope stability problem is an important issue for the safety of human beings and structures. The stability analysis of the three-dimensional (3D) slope is essential to prevent landslides, but the most important and difficult problem is how to determine the 3D critical slip surface with the minimum factor of safety in earth slopes. Basing on the slope stress field with the finite element method, a stability analysis method is proposed to determine the critical slip surface and the corresponding safety factor of 3D soil slopes. Spherical and ellipsoidal slip surfaces are considered through the analysis. The moment equilibrium is used to compute the safety factor combined with the Mohr-Coulomb criteria and the limit equilibrium principle. Some assumptions are introduced to reduce the search range of center points and the radius of spheres or ellipsoids. The proposed method is validated by a classical 3D benchmark soil slope. Simulated results indicate that the safety factor of the benchmark slope is 2.14 using the spherical slip surface and 2.19 using the ellipsoidal slip surface, which is close to the results of previous methods. The simulated results indicate that the proposed method can be used for the stability analysis of a 3D soil slope.

Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

Natural Hazards and Earth System Science ◽

10.5194/nhess-19-2079-2019 ◽

2019 ◽

Vol 19 (10) ◽

pp. 2079-2095 ◽

Cited By ~ 2

Author(s):

Michele Perrotti ◽

Piernicola Lollino ◽

Nunzio Luciano Fazio ◽

Mario Parise

Keyword(s):

Finite Element ◽

Safety Margin ◽

Structural Elements ◽

Geometrical Features ◽

Overall Stability ◽

Underground Cavities ◽

The Stability ◽

Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

E3S Web of Conferences ◽

10.1051/e3sconf/201913604023 ◽

2019 ◽

Vol 136 ◽

pp. 04023

Author(s):

Ming Zhao ◽

Ke Li ◽

Hong Yan Guo ◽

KaiCheng Hua

Keyword(s):

Limit State ◽

Stable State ◽

Simulation Software ◽

Surrounding Rock ◽

Large Section ◽

Rock Stability ◽

Geological Conditions ◽

Construction Step ◽

The Face ◽

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.