scholarly journals The Stress-Strain State of the Tunnel Lining that Crosses the Fault Zone of Soil Blocks during an Earthquake

2022 ◽  
Vol 24 (1) ◽  
pp. D9-D22
Author(s):  
Mark R. Miller ◽  
Evgeniy Y. Titov ◽  
Sergey S. Kharitonov ◽  
Yong Fang
Keyword(s):  
Fault Zone ◽  
Analytical Method ◽  
Strain State ◽  
Numerical Solutions ◽  
Numerical Models ◽  
Soil Mass ◽  
Tunnel Lining ◽  
Soil Layers ◽  
Internal Forces ◽  
Surrounding Soil

The study examines the question of the tunnel behavior under seismic or geophysical load in the zone of changes in the hardness of the surrounding soil mass. In the course of the study, the internal forces and displacements arising in the structure of a tunnel in the zone of intersection of the boundaries of soil layers with different properties, in the case when these layers move relative to each other, were determined by analytical and numerical solutions. The data obtained by the analytical method was compared to numerical models using practical examples.

scholarly journals ON ONE NUMERICAL METHOD FOR THE COMPUTING OF SEDIMENTATION OF THE SURFACE OF THE SOIL MASSIVE CAUSED BY THE CONSTRUCTION OF THE SHELL LINING OF THE TUNNEL

2018 ◽  
Vol 14 (1) ◽  
pp. 78-91
Author(s):  
Sergey B. Kosytsyn ◽  
Vladimir Y. Akulich
Keyword(s):  
Analytical Solution ◽  
Numerical Method ◽  
Strain State ◽  
Soil Mass ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Earth ◽  
Surrounding Soil

The distinctive work is aimed at the geotechnical forecast of the influence of the construction of the tunnel on the change in the stress-strain state of the surrounding soil mass, namely, the precipitations that arise on the surface of the earth. The work assumes both a numerical and an analytical solution with subsequent com-parative analysis

scholarly journals Interaction between a long pile and multi-layer underlying soils

Vestnik MGSU ◽  
2021 ◽  
pp. 168-175
Author(s):  
Zaven G. Ter-Martirosyan ◽  
Aleksandr S. Akuletskii
Keyword(s):  
Numerical Methods ◽  
Shear Modulus ◽  
Software Package ◽  
Numerical Solutions ◽  
Soil Mass ◽  
Variable Load ◽  
Soil Layers ◽  
3D Software ◽  
Pile Length ◽  
Plaxis 3D

Introduction. The majority of construction sites feature complex geotechnical conditions, as they have alternating soil layers, including loose soils. A pile foundation is the principal type of foundations constructed on these sites. This article encompasses a problem statement and a solution to the problem of interaction between a long pile and multilayer underlying soils. Materials and methods. The problem is explored in linear and nonlinear settings. The S.P. Timoshenko elastoplastic model is analyzed to describe nonlinear shear deformations. Analytical and numerical methods are employed to present the solution. The results of the analytical solution are compared with the results of the elastic problem obtained using the Plaxis 3D software package. Results. An equation designated for determining the reduced shear modulus of the multilayer soil mass is obtained. Analytical solutions are supported by the graphical solution obtained using Mathcad software. Numerical solutions are obtained using the Plaxis 3D software package. The diagrams describing the dependence of the settlement of the pile, that passes through alternating soil layers, on the load are provided. The diagrams, describing the dependence between the force, applied to the pile toe, and the pile radius in case of a variable load applied to the pile head and variable pile length are provided. Conclusions. The resulting dependence, needed to determine the reduced shear modulus of the multi-layer soil mass, demonstrates good convergence with numerical methods in the elastic setting. These solutions can be used to pre-determine the displacement of a long pile surrounded with the underlying multi-layer soil mass. The selection of an optimal correlation between the pile length and the pile diameter allows for the most effective use of the bearing capacity of the pile.

Modelling of interactions between dykes, inclined sheets and faults at Santorini volcano

2021 ◽  
Author(s):  
Kyriaki Drymoni ◽  
John Browning ◽  
Agust Gudmundsson
Keyword(s):  
Tensile Strength ◽  
Fault Zone ◽  
Numerical Models ◽  
Damage Zone ◽  
Sheet Thickness ◽  
Analytical Models ◽  
Energy Conditions ◽  
Dyke Swarm ◽  
Normal Faults ◽  
Santorini Volcano

<p>Dykes and inclined sheets are known occasionally to exploit faults as parts of their paths, but the conditions that allow this to happen are still not fully understood. Here we report field observations from a well-exposed dyke swarm of the Santorini volcano, Greece, that show dykes and inclined sheets deflected into faults and the results of analytical and numerical models to explain the conditions for deflection. The deflected dykes and sheets belong to a local swarm of 91 dyke/sheet segments that was emplaced in a highly heterogeneous and anisotropic host rock and partially cut by some regional faults and a series of historic caldera collapses, the caldera walls providing, excellent exposures of the structures. The numerical models focus on a normal-fault dipping 65° with a damage zone composed of parallel layers or zones of progressively more compliant rocks with increasing distance from the fault rupture plane. We model sheet-intrusions dipping from 0˚ to 90˚ and with overpressures of alternatively 1 MPa and 5 MPa, approaching the fault. We further tested the effects of changing (1) the sheet thickness, (2) the fault-zone thickness, (3) the fault-zone dip-dimension (height), and (4) the loading by, alternatively, regional extension and compression. We find that the stiffness of the fault core, where a compliant core characterises recently active fault zones, has pronounced effects on the orientation and magnitudes of the local stresses and, thereby, on the likelihood of dyke/sheet deflection into the fault zone. Similarly, the analytical models, focusing on the fault-zone tensile strength and energy conditions for dyke/sheet deflection, indicate that dykes/sheets are most likely to be deflected into and use steeply dipping recently active (zero tensile-strength) normal faults as parts of their paths.</p>

scholarly journals PRINCIPLES OF CALCULATION AND MONITORING OF STRESS-STRAIN STATE OF THE GRADE-SEPARATED TRAFFIC INTERCHANGES IN MINSK

2017 ◽  
Vol 2 (49) ◽  
pp. 126-134
Author(s):  
G. P. Pastushkov ◽  
V. G. Pastushkov
Keyword(s):  
Data Transmission ◽  
Work Performance ◽  
Strain State ◽  
Calculation Model ◽  
Continuous Control ◽  
Building Structures ◽  
Underground Structures ◽  
Construction Monitoring ◽  
Online Mode ◽  
Surrounding Soil

The results of scientific accompaniment and monitoring of construction of the transport interchange at the intersection of Independence Avenue and Filimonova Street over tunnels and other structures of Minsk subway. In order to ensure (in three shifts) the construction and installation works at construction of transport interchange around a number of innovative technologies in both for designing and work performance has been used. Construction monitoring envisaged continuous control of deformations and stresses of constructions of underground tunnels in the online mode and data transmission to all interested organizations. The calculation model of the existing tunnels has been developed, which includes the design of the lining and the surrounding soil massif. A theory for calculating underground structures based on the deformation of materials of building structures and geomechanical models composing a soil massif has been proposed.

scholarly journals INTERACTION OF A LONG PILE OF FINITE STIFFNESS WITH SURROUNDING SOIL AND FOUNDATION CAP

Vestnik MGSU ◽  
2015 ◽  
pp. 72-83
Author(s):  
Armen Zavenovich Ter-Martirosyan ◽  
Zaven Grigor’evich Ter-Martirosyan ◽  
Tuan Viet Trinh
Keyword(s):  
Differential Equation ◽  
Analytical Solution ◽  
Carrying Capacity ◽  
Strain State ◽  
Order Differential Equation ◽  
Deformation Modulus ◽  
First Case ◽  
Equivalent Modulus ◽  
Underlying Soil ◽  
Surrounding Soil

The article presents the formulation and analytical solution to a quantification of stress strain state of a two-layer soil cylinder enclosing a long pile, interacting with the cap. The solution of the problem is considered for two cases: with and without account for the settlement of the heel and the underlying soil. In the first case, the article is offering equations for determining the stresses of pile’s body and the surrounding soil according to their hardness and the ratio of radiuses of the pile and the surrounding soil cylinder, as well as formulating for determining equivalent deformation modulus of the system “cap-pile-surrounding soil” (the system). Assessing the carrying capacity of the soil under pile’s heel is of great necessity. In the second case, the article is solving a second-order differential equation. We gave the formulas for determining the stresses of the pile at its top and heel, as well as the variation of stresses along the pile’s body. The article is also formulating for determining the settlement of the foundation cap and equivalent deformation modulus of the system. It is shown that, pushing the pile into underlying layer results in the reducing of equivalent modulus of the system.

Numerical solutions to wave interaction with rubblemound breakwaters

1990 ◽  
Vol 17 (2) ◽  
pp. 252-261 ◽  
Author(s):  
Kevin R. Hall
Keyword(s):  
Numerical Modelling ◽  
Numerical Solution ◽  
Numerical Solutions ◽  
Scale Effects ◽  
Numerical Models ◽  
Internal Flow ◽  
Wave Interaction ◽  
Theoretical Development ◽  
Porous Media Flow ◽  
Complex Flow

The interaction of a wave with a rubblemound breakwater results in a complex flow field which is both nonlinear and turbulent, particularly within a region close to the surface of the structure. Numerical models describing internal flow in a rubblemound breakwater are becoming increasingly important, particularly as the influence of scale effects on internal flow in physical hydraulic models are becoming understood as important. A number of numerical models to predict the internal breakwater flow kinematics have been produced in the past two decades. This paper provides a review of the state-of-the-art of numerical modelling of wave interaction with rubblemound breakwaters. Details of the theoretical development and the resulting numerical solution techniques are presented. Methods for incorporating secondary effects such as two-phase (air–water) flow, inertia, and unbalanced boundary conditions are discussed. Limitations of the models resulting from the validity of the assumptions made in order to effect a numerical solution are discussed. Key words: breakwaters, internal flow, porous media flow, numerical modelling, rubblemound breakwaters.

scholarly journals Nonlinear subgrade reaction solution for circular tunnel lining design based on mobilized strength of undrained clay

2018 ◽  
Vol 55 (2) ◽  
pp. 155-170 ◽  
Author(s):  
Dong-ming Zhang ◽  
Kok-Kwang Phoon ◽  
Qun-fang Hu ◽  
Hong-wei Huang
Keyword(s):  
Design Method ◽  
Large Strain ◽  
Tunnel Lining ◽  
Subgrade Reaction ◽  
Circular Tunnel ◽  
Nonlinear Solution ◽  
Reaction Solution ◽  
Tunnel Convergence ◽  
Tunnel Lining Design ◽  
Internal Forces

This paper presents a nonlinear solution of a radial subgrade reaction–displacement (pk–ur) curve for circular tunnel lining design in undrained clay. With the concept of soil shear strength nonlinearly mobilized with shear strain, an analytical solution of pk is obtained using the mobilized strength design method. Two typical deformation modes are considered, namely oval and uniform. A total of 197 orthogonally designed cases are used to calibrate the proposed nonlinear solution of pk using the finite element method with the hardening soil model. The calibration results are summarized using a correction factor, η, which is defined as the ratio of pk_FEM to pk_MSD. It is shown that η is correlated to some input parameters. If this correlation is removed by a regression equation, f, the modified solution f(pk_MSD) agrees very well with pk_FEM. Although in reality the mobilized soil strength varies with principal stress direction, it is found that a simple average of plane strain compression and extension results is sufficient to produce the above agreement. The proposed nonlinear pk–ur curve is applied to an actual tunnel lining design example. The predicted tunnel deformations agree very well with the measured data. In contrast, a linear pk model would produce an underestimation of tunnel convergence and internal forces by 2–4 times due to the overestimation of pk at a large strain level.

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