scholarly journals Evaluation of earth pressure on buried pipes and stability of surroundings according to construction condition

2015 ◽  
Vol 18 (1) ◽  
pp. 64-72
Author(s):  
Son Truong Bui
Keyword(s):  
Limit State ◽  
Earth Pressure ◽  
Underground Water ◽  
Actual Condition ◽  
Underground Structures ◽  
Buried Pipes ◽  
The Earth ◽  
Geological Conditions ◽  
The Stability ◽  
Construction Condition

Earth pressure on buried pipes structure depends not only on soil type, shape and dimension of structure but also on depth, shape and dimension of excavated holes and other factors such as structure load, underground water level. Based on the selected and modified computational scheme with self-established program, the earth pressure on pipe structures according to the construction condition is evaluated and analysed. It is recommended to choose the buried depth for structure in “cut and cover” excavation method so that the influence of earth pressure is reasonably steady from the buried point downward. The replacement of backfill material to cohesive material partially can help to reduce significantly the earth pressure on the buried structure. In addition, evaluation of the the degree of approaching to limit state in surroundings in bored tunnelling excavation allows for analysing the stability in various geological conditions according to the appearance of plastic zone. The research results are useful for calculating and arranging underground structures reasonably in actual condition

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

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 ◽  
The Stability

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.

Fundamentals of engineering Geology

2021 ◽  
Author(s):  
Nikolay Platov
Keyword(s):  
Vocational Education ◽  
Engineering Geology ◽  
Underground Water ◽  
Geological Structure ◽  
Federal State ◽  
Construction Site ◽  
Secondary Vocational Education ◽  
The Earth ◽  
Geological Conditions ◽  
State Educational

The theoretical and practical foundations of engineering geology, the geological structure and origin of the Earth are described, the minerals of rocks and the rocks themselves of igneous, sedimentary and metamorphic origin are considered. Considerable attention is paid to the geomorphological, geodynamic, and hydrogeological conditions of the construction site with the allocation of three types of underground water: upper water, ground water, and inter-reservoir. The dynamics of the development of various forms of relief caused by endogenous and exogenous processes is given. The zonal elements of engineering and geological conditions of any construction site are given. Meets the requirements of the federal state educational standards of secondary vocational education of the latest generation. For students of secondary vocational education institutions studying engineering geology.

A Study on the Earth Pressure of Top Culvert of High Embankment

2012 ◽  
Vol 178-181 ◽  
pp. 1104-1111 ◽  
Author(s):  
Shi Sheng Zhou ◽  
Xi Meng Sun ◽  
Jun Peng ◽  
Jia Lv
Keyword(s):  
Finite Element ◽  
Earth Pressure ◽  
Structure Design ◽  
Actual Condition ◽  
Test Model ◽  
Actual Situation ◽  
Theoretical Derivation ◽  
Finite Element Software ◽  
The Earth ◽  
Element Simulation

Based on the extensive research and analysis of actual condition of top culvert of high embankment, a calculation theory for the earth pressure of top culvert was presented. The theory could optimize the structure design for culverts, and reduce the waste of resource. First, based on the simplified assumption of the stress of soil on the top culvert and the analysis of single unit of the load on the top culvert, the calculation formula of earth pressure on different position of top culvert was presented by theoretical derivation. Then, to verified the results by using scaled test model and ABAQUS finite element software. Through the comparison with the traditional calculation theory and finite element simulation, we could prove that the calculation theory is more tallies with the actual situation of the earth pressure on the top culvert.

Study on the Calculation Method of Earth Pressure on Retaining Wall in the Mode of Translation

2015 ◽  
Vol 1089 ◽  
pp. 292-298
Author(s):  
Zhi Xiong Zhang ◽  
Yong Gang Li ◽  
Chao Tian
Keyword(s):  
Calculation Method ◽  
Retaining Wall ◽  
Limit State ◽  
Earth Pressure ◽  
Friction Angle ◽  
Displacement Effect ◽  
Translational Movement ◽  
The Earth ◽  
Translational Displacement ◽  
Movement Effect

Focusing on rigid retaining wall under translation movement mode, the earth pressure under non-limit state considering translational movement effect is studied. Considering the translational displacement effect of internal friction angle of the backfill and the wall soil friction angle,we established the relation formula between internal and external friction angle and displacement and got strength and distribution of horizontal earth pressure, strength and the acting point of resultant force on retaining walls at any displacement in mode of translation. We also compare the calculation of earth pressure obtained by the calculation method proposed in this paper with the measured values of the model and found and they are on the whole the same.

scholarly journals Factor Affecting the Magnitude and the Direction of the Pressure Exerted on the Gravity Retaining Wall

2020 ◽  
Vol 9 (5) ◽  
pp. 1340-1343
Keyword(s):  
Water Table ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Soil Pressure ◽  
Gravity Retaining Wall ◽  
The Earth ◽  
Backfill Soil ◽  
Dry Soil ◽  
The Stability ◽  
External Loads

Gravity retaining wall are structures used to retain the soil by its weight .the stability of such type of walls depend on the magnitude and direction of the horizontal forces exerted by soil . it found that there is many factors affect the value and the acting point of acting. Based on this, a study was conducted to investigate the effect of water table, external vertical loads, sloping of the backfill and the type of the backfill soil. It show that, the value of the horizontal soil pressure increase from147KN/m' on dry soil to about 307 KN/m' as the soil become saturated.also,effect of external loads are studied , and show its increase the total horizontal forces of the soil pressure. Sloping the backfill soil behind the retaining wall also great effect on the earth pressure. The type of the backfill soil behind the retaining wall also investigated and found its effect of the earth forces.

scholarly journals Role of Geologists During Tunnel Construction and Face Mapping to Decide the Required Tunnel Support

2021 ◽  
Vol 9 (9) ◽  
pp. 2080-2081
Author(s):  
Deepak Parkash Gupta
Keyword(s):  
Failure Modes ◽  
Design Stage ◽  
Underground Structures ◽  
Tunnel Support ◽  
Execution Phase ◽  
Geological Conditions ◽  
Ground Conditions ◽  
The Stability ◽  
Stress Behaviour

Abstract: The stability of underground structures is an important aspect during design, construction and execution Phase. Depending on the geotechnical conditions and influencing factors, different failure modes during execution mode can be expected, and depending on the potential failure modes, boundary conditions and specific construction measures to ensure stability have to be chosen. The most important is developing a realistic estimate of the expected ground conditions and their potential behaviour/failure modes as a result of the excavation. The variability of the geological conditions including local ground structure, ground parameters, stress and ground water conditions requires that a consistent and specific procedure is used. The other is to design an economic and safe excavation and support method for the determined ground behaviours. The discussion of role of geologists during design stage is beyond the scope of the present study. The main objective of this study is to present the role of geologists during the construction stage. Keywords: Geologist, Stress, Behaviour, RMR, Q Value, RQD, Rock Mass

scholarly journals Estimation of Optimal Opening Rate of Rahmen Bridge with Open Wall through Moment Analysis of Corner

2020 ◽  
Vol 20 (4) ◽  
pp. 173-184
Author(s):  
Sun-Joon Park ◽  
Yeongseok Kim ◽  
Ikjoong Kim ◽  
Sunhee Cho ◽  
Namkyung Hong ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Design Method ◽  
Limit State ◽  
Earth Pressure ◽  
Moment Analysis ◽  
Width Ratio ◽  
Bending Moments ◽  
Height Ratio ◽  
Limit State Design ◽  
The Earth

The earth pressure acting on the wall of a Rahmen bridge generates significant bending moments at the corners. These moments create problems in the wall in terms of stability and economy. In this study, a Rahmen bridge with an open wall was adopted to solve the problems highlighted above, and its optimal opening rate was estimated. Structural analysis was performed for 36 analytical cases by applying the limit state design method according to lengths of 20 and 15 m for the closed height ratio (h/H) and closed width ratio (b/B) of the wall. Within the scope of this study, in the Rahmen bridge with a 20 m span, it is desirable to design an open wall to satisfy the 0.4 ≤ h/H ≤ 0.614 and 0.75 ≤ b/B < 1 conditions when adequate reinforcement is provided at the wall end in contact with the haunch. Additionally, an open wall should be designed for the 15 m span Rahmen bridge to satisfy the conditions of 0.229 ≤ h/H ≤ 0.586 and 0.833 ≤ b/B < 1 when suitable reinforcement is provided at the slab end in contact with the haunch. Therefore, the Rahmen bridge with an open wall can be used instead of the conventional Rahmen bridge, considering the economy and on-site applicability factors.

scholarly journals Stability analysis of composite I-shaped masonry reinforced retaining wall

2020 ◽  
Vol 198 ◽  
pp. 02032
Author(s):  
Wu Yuedong ◽  
Zhang Lei ◽  
Xu Nan ◽  
Lui Jian
Keyword(s):  
Numerical Simulation ◽  
Retaining Wall ◽  
Single Layer ◽  
Earth Pressure ◽  
Horizontal Displacement ◽  
Finite Element Software ◽  
The Earth ◽  
Overall Stability ◽  
The Stability ◽  
Reinforced Retaining Wall

Based on the actual project, the influence of geogrid on the stability of the retaining wall of the single-layer masonry reinforced retaining wall is studied through field test and finite element software ABAQUS numerical simulation. The influence of geogrid on the stability of the retaining wall was determined by analyzing the changes in the pressure of the backfill, the displacement of the retaining wall and the strain of the geogrid, and changing the length and spacing of the geogrid through the controlled variable method. The results show that the geogrid can limit the horizontal displacement of the soil, balance the earth pressure, and improve the overall stability of the retaining wall. By increasing the length of the geogrid and reducing the distance of the geogrid, the design of the retaining wall is optimized, which has good economic and time benefits.

scholarly journals Comparative analysis of stability of large diameter steel cylinder based on FEM and limit equilibrium

2020 ◽  
Vol 198 ◽  
pp. 03026
Author(s):  
Chang-yi Yu ◽  
Ming-yue Lu
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Reduction Method ◽  
Limit Equilibrium ◽  
Large Diameter ◽  
Earth Pressure ◽  
Steel Cylinder ◽  
The Earth ◽  
Analysis Of Stability ◽  
The Stability

The stability mechanism of large-diameter steel cylinder under fill load has not yet formed a complete theory. In order to calculate the stability of the steel cylinder island arm structure in a certain project, the limit equilibrium and finite element method are used in this paper. The limit equilibrium method is based on the limit equilibrium of the soil inside and outside the steel cylinder, taking into account the earth pressure and friction force on the cylinder, and using moment equilibrium to calculate its stability coefficient. Secondly, the finite element strength reduction method is adopted to analyze the stability of the steel cylinder island arm structure by using strength parameters to correlate with the temperature field and changing the boundary conditions of the temperature field. The results and analysis methods of this paper provide references for the construction and design of the same type of projects.

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