Influence of Salt Solutions on the Undrained Shear Strength and the Clogging of Smectite-Quartz Mixtures

Spagnoli, Giovanni; Feinendegen, Martin; Fernández-Steeger, Tomás Manuel

doi:10.2113/gseegeosci.17.3.293

Cited by 40 publications

(3 citation statements)

References 13 publications

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“…In severe cases, the increase of rotation torque of the cutter head can result in a significant fluctuation of shield parameters, blocking of mud pipes, and so on, affecting the safety and efficiency of construction [8][9][10][11]. Therefore, the soil adhesion on the cutter surface is one of the important reasons for the occurrence of the mud cake [12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Experimental Research on the Adhesion Characteristics of Clay to Structures with Different Materials

Qiu

Zhang

2021

Geofluids

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When the shield machine passes through the clay layer, the clay debris cut by the cutter head usually adheres to the surface of the cutter head and is easy to form mud cakes after extrusion, which affects the safety and efficiency of construction. For the structure made of different materials, due to the different surface properties, the adhesion characteristics of clay are also different. So, selecting proper materials for the soil contacting parts in the shield machine can effectively reduce the adhesion between the structure and soil, decrease the clay adhering to the surface of the shield cutter, and reduce the possibility of further productions of mud cake. Therefore, studying the adhesion properties of clay to different materials and understanding the adhesion rule of clay to soil contacting structures are of guiding significance when selecting the materials of soil contacting parts. In this paper, the adhesion properties of cohesive soil to commonly used construction materials were studied by a self-made adhesion test device, including steel, iron, copper, aluminum, and engineering plastics (polyamide). According to the findings, the separation process of adhesion between soil and the structure by an external force can be divided into four stages, which are the adhesive elastic development stage, adhesive plastic development stage, failure stage, and detachment stage. The adhesion forces and the amount of soil adhered to the structures made of the selected materials are found to vary from each other. The adhesion forces ranked from high to low are, respectively, found on the iron, plastic, aluminum, steel, and copper surfaces. The material with the most amount of adherent soil is aluminum, followed by iron, steel, copper, and plastic.

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Section: Introductionmentioning

confidence: 99%

Experimental Research on the Adhesion Characteristics of Clay to Structures with Different Materials

Qiu

Zhang

2021

Geofluids

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“…The clay debris cutoff will adhere to the surface of the cutter head when the shield cutter head passes through the clay layer and forms solid or semisolid masses by the compaction of cutter head, then sticks to the cutter head and blocks it decreasing the penetration so that the efficiency of shield excavation reduces [1][2][3][4]. The adhesion of soil is one of the important reasons for the formation of mud cake on the surface of the cutter head [5][6][7][8][9][10]. The existence of mud cake will not only lead to the increase of the torque of the shield cutter, but also block the suction opening of the slurry discharge pipe, which will seriously affect the shield construction technology and construction safety.…”

Section: Introductionmentioning

confidence: 99%

Experimental Research on the Impact of Temperature on the Adhesion Characteristics of Soil-Structure Interface

et al. 2020

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Under the working condition of mud cake, the continuous action between the shield cutter head and the soil on the excavation surface can generate high temperature in the process of shield tunneling and excavation, which changes the characteristic of the adhesion between the soil and the cutter head to intensify the phenomenon of making a mud cake on cutter, finally leading to a vicious circle. To study the effect of temperature on the characteristics of the adhesion of the soil on the surface of the structure, the soil adhesive situation and adhesion force at different interface temperatures were tested through a self-made experiment device. According to the result, it was indicated that the moisture content has a significant effect on the adhesion force of the soil, and the adhesion force firstly increased and then decreased with the increased of the moisture content and reached the maximum value near the plastic limit moisture content. The adhesion force changes very gently when the interface temperature is low. When the temperature reached 50°C, the adhesion force continues to increase as the interface temperature continuously increases except for the soils with high moisture content; moreover, the interface temperature has a great influence on the content of soil adhered on the structure surface. As for the soil with moderate moisture content ( ω = 21.21 ~ 31 %), this content of the adhered soil increased exponentially with the increase of interface temperature; this content firstly decreased and then increased when the moisture content was high. When the soil was dry, there was almost no adhered soil on the surface and the interface temperature had no effect on the adhesive situation. By comparing and analyzing the adhesion state of the soil on the surface of the structure, the influence of temperature on the adhesion characteristics is mainly reflected on the variation of the soil moisture content within the influence range of the interface, the variation of the energy required for the destruction of the adhesion interface, and the change of the location of the weakest antistripping plane induced by both before. This research can better understand the law of formation and development of mud cakes and provided a new idea of solving the problem of mud cakes on the cutter head.

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“…Adhesion can be expected only in cohesive soils that have at least 10-20% clay mineral contents. Basically, clogging can stem from the adhesion that occurs in the interface of clay minerals and a metal surface (Spagnoli 2011). Fountaine (1954) was the first researcher to propose a theory on the mechanisms of adhesion.…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of clayey soil relevant for clogging potential

Alberto-Hernandez

Kang

et al. 2017

International Journal of Geotechnical Engineering

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Due to its advantages, including reduced operation time and cost, tunneling with boring machines in urban areas has become a popular technique over handtunneling or open-trench excavations. However, tunneling in clayey soil poses a great challenge since the mechanical and physical properties of clays cause different issues, one of which is clogging. To solve this problem, engineers have treated the soils with different soil conditioners in order to change their rheological properties, improve their manageability, and eliminate undesirable characteristics. However, the root of this problem is the lack of understanding the phenomenon and characterizing it on the framework of soil mechanics. By considering the use of polymers, this paper aims to provide information regarding the theory involved in this mechanism and the factors influencing clogging potential. The authors present a systematic study of the physical and mechanical properties of plain soil and conditioned soil, which includes a direct shear test, vane shear test, and Atterberg limits test. Results show that the initial water content, roughness of shear plate, and percentage of additive have a significant effect on the clogging potential. Additionally, the results are plotted on an empirical diagram to understand the clogging potential by relating the clogging potential to soil properties.

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Influence of Salt Solutions on the Undrained Shear Strength and the Clogging of Smectite-Quartz Mixtures

Cited by 40 publications

References 13 publications

Experimental Research on the Adhesion Characteristics of Clay to Structures with Different Materials

Experimental Research on the Adhesion Characteristics of Clay to Structures with Different Materials

Experimental Research on the Impact of Temperature on the Adhesion Characteristics of Soil-Structure Interface

Mechanical properties of clayey soil relevant for clogging potential

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