scholarly journals Study of the shear strength evolution over time of two-component backfilling grout in shield tunnelling

2021 ◽  
pp. e00689
Author(s):  
Carmine Todaro ◽  
Andrea Carigi ◽  
Daniele Peila ◽  
Daniele Martinelli
Keyword(s):  
Shear Strength ◽  
Strength Evolution ◽  
Two Component ◽  
Shield Tunnelling ◽  
Over Time

Test of Solidification Characteristics of Grouting and the Effect on Strata Deformation in Shield Tunnelling

2012 ◽  
Vol 568 ◽  
pp. 80-84
Author(s):  
Xiao Chun Zhong ◽  
Wei Ke Qin ◽  
Hai Wang
Keyword(s):  
Numerical Model ◽  
Rigid Body ◽  
Active Control ◽  
Calculation Method ◽  
Civil Engineering ◽  
Test Results ◽  
Shield Tunneling ◽  
Shield Tunnelling ◽  
Strata Deformation ◽  
Over Time

Back-fill Grouting is a key procedure for the active control of strata settlement during shield tunnelling in civil engineering. The paper studies the stress - strain characteristics of grouting and the state of grout, which changes from liquid to solid over time and is simulated by variable rigid body. The model of flowing state are divided in four phases from liquid-plastic to rigid state. The paper establish a numerical model of shield tunnelling in civil engineering with the consideration of characteristics of grout deformation, and has analyzed law of strata settlement. The test results show that the calculation method can well accord with the four stages of strata deformation, and can more accurately reflect the process of strata deformation caused by shield tunneling.

Performance of Two-Component Systems with Imperfect Repair

2012 ◽  
pp. 292-304
Author(s):  
Mohammed Hajeeh
Keyword(s):  
Time To Failure ◽  
Repairable Systems ◽  
Two Component System ◽  
Imperfect Repair ◽  
Component Systems ◽  
Two Component ◽  
Operational Systems ◽  
Two Component Systems ◽  
Operational Probability ◽  
Over Time

Operational systems deteriorate over time and eventually fail by the failure of one or more of their components. Failed components are either replaced or repaired, and replacement is usually expensive. This article examines the behavior of repairable systems with imperfect repair, where a failed component is repaired once or more depending on factors such as repair cost, level of deterioration, and criticality of the component. When these systems are subjected to a customer use environment, their performance must endure different conditions. In imperfect repair, the performance of the system lessens after each failure. Three models of a two-component system studied are the series, parallel, and standby configurations, and the components are identical and independent. A closed form analytical expression for steady state operational probability is derived for different configurations under exponential distribution time to failure and repair time. Two examples are then discussed thoroughly.

scholarly journals Kajian Ketahanan Batuan Clay Shale Formasi Jatiluhur di Sentul City Jawa Barat

PROMINE ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 26-32
Author(s):  
Revia Oktaviani ◽  
Paulus P Raharjo ◽  
Imam A Sadisun
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Test Results ◽  
Durability Test ◽  
Indirect Contact ◽  
Water Research ◽  
Clay Shale ◽  
High Durability ◽  
Slake Durability Test ◽  
Over Time

The mechanical properties of Clay Shale are very unique. When it is dry, it shrinks and hardens, butwhen it absorbs water, it swells and to some extent loses its shear strength so that the drop-instrength can occur suddenly even with its own weight. Due to the nature of the swell-shrink that arestrongly influenced by climate and weather, clay shale durability may decrease over time when indirect contact with air and water. Research on clay shale was done in Sentul City, Bogor - West Java,Indonesia on Jatiluhur formation, using dynamic slaking (slake durability test) and slaking static test.Dynamic slacking test is done in three times i.e. after sampling, after 3 months and after 9 months.Slake durability test results from 3 different drilling points, shows that within 9 months, has not seenthe decreasing effect of durability. With a low Plasticity index, the durability research in Sentul City isin medium durability to medium-high durability classification.

Interaction between Cement Clinker Constituents and Clay Minerals and their Influence on the Strength of Cement-Based Stabilized Soft Clay

2021 ◽  
Author(s):  
Jun Wu ◽  
Zuhua Deng ◽  
Yongfeng Deng ◽  
Annan Zhou ◽  
Yunsheng Zhang
Keyword(s):  
Clay Minerals ◽  
Clay Mineral ◽  
Soft Clay ◽  
Cement Clinker ◽  
Mixing Process ◽  
Reaction Efficiency ◽  
Strength Evolution ◽  
Alkaline Conditions ◽  
Over Time

The strength of cement stabilized clay is less than that of concrete and mortar and shows a distinct variability owing to the existence of various clay minerals. To better understand the cement-clay reactions and the strength generation, two artificial clays with the unique clay mineral and major strength-producing constituents of cement clinker were investigated via mechanical, compositional, and microstructural analyses. Results show that C3A-stabilized clay gains strength rapidly in the first three days, but this favourable tendency vanishes over time. After 90 days of curing, the strength of C3S-stabilized clay is about four times that of the corresponding C3A-stabilized clay, indicating the remarkable long-term stabilization efficiency of C3S. Furthermore, clay minerals primarily draw into strength evolution in the reaction process. Despite that bentonite is more reactive than kaolin as long as the highly alkaline conditions persist, it has a higher probability to flocculate into large aggregates during the mixing process, which may impair the reaction efficiency and even brings adverse stabilization effects, suggesting the importance of uniformity control.

Sizing effects on the interfacial shear strength of a carbon fibre reinforced two-component thermoplastic polymer

2019 ◽  
Vol 127 ◽  
pp. 105622 ◽  
Author(s):  
Andreas Hendlmeier ◽  
Lucas I. Marinovic ◽  
Salwan Al-Assafi ◽  
Filip Stojcevski ◽  
Luke C. Henderson
Keyword(s):  
Shear Strength ◽  
Carbon Fibre ◽  
Interfacial Shear Strength ◽  
Interfacial Shear ◽  
Thermoplastic Polymer ◽  
Two Component

scholarly journals Consolidated Undrained Triaxial Compression Tests and Strength Criterion of Solidified Dredged Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Jianwen Ding ◽  
Xusong Feng ◽  
Yupeng Cao ◽  
Sen Qian ◽  
Feng Ji
Keyword(s):  
Shear Strength ◽  
Water Pressure ◽  
Triaxial Compression ◽  
Strength Criterion ◽  
Undrained Shear Strength ◽  
Compression Tests ◽  
Dredged Materials ◽  
Strength Evolution ◽  
Triaxial Compression Tests ◽  
Undrained Shear

Consolidated undrained triaxial compression tests were performed to investigate the shear strength behavior of the solidified dredged materials (SDM). The variation law of deviator stress and excess pore water pressure with the increase of the applied confining pressure was investigated. It is found that the shear strength envelope is consisted of two lines, and there exists a transitional stress on the intersection point. The undrained shear strength develops slightly with the increase of applied normal stress in the preyield state. However, the undrained shear strength increases significantly in the postyield state, and the strength envelope is nearly a straight line with the extension through the origin. Based on the triaxial test data and the binary medium model, a strength criterion considering strength evolution mechanism is proposed and the relevant parameters of the strength criterion were discussed. Comparisons of the predicted results and experimental data demonstrate that the proposed strength criterion can properly describe the strength evolution rules of the SDM.

scholarly journals Repetitive Overseeding for Ecological Management of Grass Playing Fields

HortScience ◽  
2021 ◽  
pp. 1-8
Author(s):  
Maria Gannett ◽  
Natalie Bray ◽  
Joellen Lampman ◽  
Jennifer Lerner ◽  
Kathy Murray ◽  
...  
Keyword(s):  
Shear Strength ◽  
Soil Moisture ◽  
Weed Management ◽  
Soil Compaction ◽  
Management Program ◽  
Management Tool ◽  
Grass Cover ◽  
Bare Ground ◽  
Playing Fields ◽  
Over Time

Because of public concern about exposing children to pesticides, legislation restricting its use on school playing fields has increased. One way to manage weeds without chemical herbicides is overseeding or the practice of repetitively seeding with a rapidly germinating turfgrass species. Overseeding for broadleaf weed control was tested on eight fields in Central New York (CNY) for three seasons and 40 fields across the northeastern United States for two seasons. Half of each field was treated each season by overseeding Lolium perenne L. (perennial ryegrass) three to five times each season for a total of 731 kg seed/ha (15 lb per 1000 ft2). Changes in the percent broadleaf weeds, grass, bare ground, soil moisture, Dark Green Color Index (DGCI) of grass cover, depth to soil compaction, and shear strength were measured after each treatment. The percent broadleaf weeds decreased and the percent grass cover increased due to overseeding in the Northeast fields, but not in CNY fields. Depth to compaction, percent soil moisture, and shear strength varied over time in the Northeast fields, and the percent bare ground, DGCI, and soil moisture varied over time in CNY fields. DGCI in the Northeast and soil compaction in CNY were affected by the interaction of overseeding × time. Although overseeding can be a beneficial weed management tool and affect other turf and soil traits in an integrated turf management program, monitoring environmental conditions and supporting field maintenance routines are critical weed management strategies for maintaining healthy turfgrass.

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