The new clay mud and its improvement effects of tunnels

Yang, Yiqin; Wang, Guihe; Li, Hong-an; Huang, Xiaona

doi:10.1016/j.clay.2013.02.021

Cited by 15 publications

(9 citation statements)

References 7 publications

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“…in the poor mechanical characteristics of soils in complex geological formations with large groundwater level [1][2]. In order to ensure tunneling advances in a stratum containing different types of soil, the excavationof soil must be performed by adding modified material to change physical and mechanical properties making a soil with good plastic flow state, low friction angle and in some cases with low permeability.…”

Section:  Abstract: Chemical Foam Is Being Used More Frequently Withmentioning

confidence: 99%

“…In order to ensure tunneling advances in a stratum containing different types of soil, the excavationof soil must be performed by adding modified material to change physical and mechanical properties making a soil with good plastic flow state, low friction angle and in some cases with low permeability. The importance of soil conditioning practice for EPB methods has conducted to high research efforts around the world [1]. Since the state of the art established by Milligan (2000) [2], many laboratory tests using newly developed devices [3], have brought insight into the working mechanisms of the different products and into the resulting soil behavior of different soils [4].…”

Section:  Abstract: Chemical Foam Is Being Used More Frequently Withmentioning

confidence: 99%

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Experimental and Modeling of Shear Mechanical Behavior of Soil Conditioned With Foaming Agent

Selmi

Kacem

Jamei

et al. 2019

IJITEE

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Chemical foam is being used more frequently with Earth Pressure Balance (EPB) shields to achieve underground works, which present a rising interest in the excavation technique. During tunneling with an Earth Pressure Balance shield in clayey soil, clogging of the clay occurs, leading to blocking the cutting head and clog then the shield chambers. Surfactants are commonly used as conditioning agents to reduce clay stickiness. This treatment leads to a change in the mechanical properties of conditioned soil. This paper aims tostudy the shear strength behavior of foam-conditioned soil basing on triaxial tests in the undrained consolidated conditions. Experimental results are modeled using the finite element code COMSOL Multiphysics with the aim of analyzing the effect of the percentage of foam on the shear strength behavior. The soil mixture made from 40% of kaolinite and 60% of sand was conditioned with a foaming agent based on anionic surfactant. Consolidated undrained triaxial tests have been performed in order to explain the effect of foam. Results show that foam reduces the shear stress thanks to their weak stiffness. Shear strength stress is affected by the percentage of the foam in the mixture before shearing by reduce the shear strength of the conditioned soil. Soil-foam mixture has been modeled as a medium containing spherical pore inclusions with a low stiffness compared to the stiffness of unconditioned soil. Stiffness of bubbles inclusions was identified using one of the known homogenization models for composite materials. Results show that the reduce shear stress strength is affected by the percentage of inclusions in the matrix. It confirms the friction angle of composite material decrease as function of the percentage of gas bubbles inclusion in the matrix.

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Section:  Abstract: Chemical Foam Is Being Used More Frequently Withmentioning

confidence: 99%

Section:  Abstract: Chemical Foam Is Being Used More Frequently Withmentioning

confidence: 99%

Experimental and Modeling of Shear Mechanical Behavior of Soil Conditioned With Foaming Agent

Selmi

Kacem

Jamei

et al. 2019

IJITEE

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“…Among these tests, the mixing test is used to imitate the real mixing process in the soil chamber [14], and it is necessary to mix the soil conditioner with the tested soils in laboratory tests [15]. The variation of the electric motor power, the mixing time necessary to obtain a homogeneous mixture, and the quality and behavior of the mixture could be observed and evaluated during the evolution of the foam injection in the tested soil [13].…”

Section: Introductionmentioning

confidence: 99%

“…The variation of the electric motor power, the mixing time necessary to obtain a homogeneous mixture, and the quality and behavior of the mixture could be observed and evaluated during the evolution of the foam injection in the tested soil [13]. Some mixing tests have been carried out in previous studies [14][15][16]. The slump test [17], which is originally used for concrete materials, has been intensively used to evaluate the characteristics of conditioned soils in EPBS tunneling [3,5,[12][13][14]16,[18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Effects of Soil Conditioning on Characteristics of a Clay-Sand-Gravel Mixed Soil Based on Laboratory Test

Wei

Wang

et al. 2020

Applied Sciences

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Soil conditioning is of great significance for tunneling in soft ground with earth pressure balance shield (EPBS) machines, which leads to safe, highly efficient, and high-quality tunneling. To study the effects of soil conditioning on properties of a clay-sand-gravel mixed soil encountered in an EPBS tunneling project in Beijing, a series of geotechnical test methods was carried out based on laboratory test in this paper. The decay behaviors of foam particles generated by the Waring-Blender method were studied first using the image particle analysis system, and then the feasibility of soil conditioning on the mixed soil was qualitatively and quantitatively assessed through the mixing test, slump test, and friction coefficient test. The preliminary test results indicate that drainage of water in liquid film plays an important role in the decay of foam microstructure. The viscosity and flowability of the conditioned soil were modified dramatically by using various amount of water and foam, and a suitable state meeting the requirement of EPBS machines was obtained. The net power and mixing time, which reflects the interaction between the blending rods and tested soils, as well as the slump value, providing the overall indication for liquidity of the conditioned soils, and friction coefficient, reflecting the friction between steel and tested soils, were used to provide insight into the variation in viscosity and flowability of the tested soils.

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“…Yang and Li proposed a three-dimensional collapse failure mechanism, and investigated the ground surface settlements and failure mechanism above large-diameter shield tunnels under different supporting pressures [9]. Yang et al did some research about soil improvement techniques to guarantee the stability of excavation face [10, 11]. In order to observe the contour of failure surface, Takano et al used X-ray computed tomography scanner; it was suggested that the contour of the failure surface can be simulated with two log-spirals in the vertical cross-sections and elliptical contour in the horizontal cross-sections.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Face Stability during Excavation of Double‐O‐Tube Shield Tunnel

Yang

Zhou

et al. 2013

The Scientific World Journal

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This paper focuses on the face stability analysis of Double-O-Tube shield tunnel. This kind of analysis is significant to ensure the safety of workers and reduce the influence on the surrounding environment. The key point of the stability analysis is to determine the supporting pressure applied to the face by the shield. A collapse failure will occur when the supporting pressure is not sufficient to prevent the movement of the soil mass towards the tunnel. A three-dimensional collapse failure mechanism was presented in this paper. Based on the mechanism of a single circular shield tunnel, the mechanism of Double-O-Tube shield tunnel was established by using the fact that both of the mechanisms are symmetrical. Then by means of the kinematic theorem of limit analysis, the numerical results were obtained, and a design chart was provided. The finite difference software FLAC3D was applied to investigate the face failure mechanism of DOT shield tunnel established in this paper; the critical supporting pressures of the collapse failure mechanism in different strata (sand and silt) were calculated. Through comparative analysis, the theoretical values were very close to the numerical values. This shows that the face failure mechanism of DOT shield tunnel is reasonable, and it can be applied to the sand and silt strata.

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The new clay mud and its improvement effects of tunnels

Cited by 15 publications

References 7 publications

Experimental and Modeling of Shear Mechanical Behavior of Soil Conditioned With Foaming Agent

Experimental and Modeling of Shear Mechanical Behavior of Soil Conditioned With Foaming Agent

Effects of Soil Conditioning on Characteristics of a Clay-Sand-Gravel Mixed Soil Based on Laboratory Test

Analysis of Face Stability during Excavation of Double‐O‐Tube Shield Tunnel

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