scholarly journals Step fixings of vertical trench walls to prevent ground failure

2021 ◽  
Vol 274 ◽  
pp. 06006
Author(s):  
Rustam Khuziakhmetov
Keyword(s):  
Slope Angle ◽  
Construction Materials ◽  
Strength Properties ◽  
Natural Slope ◽  
Ground Failure ◽  
Safety Requirements ◽  
Strict Compliance ◽  
Vertical Walls ◽  
Conditions Of Work ◽  
Construction Works

The most commonly used designs for securing vertical walls of trenches and excavations in the actual conditions of work in them do not allow for strict compliance with regulatory safety requirements. To prevent ground failure in trenches and excavations, you can develop ground with a slope angle smaller than the natural slope angle. Development of excavations with vertical walls without securing them is limited to their depth depending on the strength properties of the ground. When excavating to a depth of up to 2-3 m the vertical walls of trenches and excavations must be secured. In this case, the development and backfilling of such excavations should be carried out using constructive solutions (e.g. anchoring), which in original combinations with modern construction materials and technologies allow various construction works to be safely performed in them.

General concept of determining the parameters of non-mining walls of ultra-deep diamond deposits development open pits

2021 ◽  
pp. 48-53
Author(s):  
I. V. Zyryanov ◽  
A. N. Akishev ◽  
I. B. Bokiy ◽  
N. M. Sherstyuk
Keyword(s):  
Rock Mass ◽  
Structural Relaxation ◽  
Slope Angle ◽  
Field Tests ◽  
Friction Angle ◽  
Strength Properties ◽  
Strength Characteristics ◽  
Open Pit ◽  
Open Pit Mining ◽  
Relaxation Coefficient

A specific feature of open pit mining of diamond deposits in Western Yakutia is the construction of the open pits in the zone of negative ambient temperatures, which includes thick permafrost rock mass, and which is at the same time complicated by the influence of cryogenic processes on deformation of pit wall benches. The paper presents the comparative analysis of strength characteristics in frozen and thawed rocks, stability of benches during mining, the general geomechanical approach to the determination of parameters of non-mining walls of the ultra-deep open pit diamond mines, and the parameters of nonmining walls and benches. Optimization of open pit wall configuration should primarily be based on the maximum utilization of the strength properties of frozen rocks in combination with the development of new approaches, calculation schemes and methods for assessing stability of open pit walls and benches of unconventional design, including the non-mining vertical benches. The main design characteristic that determines the parameters of open pit walls is the structural tectonic relaxation coefficient, which specifies the calculated value of cohesion in rock mass. For the diamond deposits, the values of the structural relaxation coefficient were obtained in a series of field tests and back calculations. Full-scale tests were carried out both during exploration operations in underground mines and in open pits. The accuracy of determining the values of the structural relaxation coefficient in the range of 0.085–0.11 is confirmed by the parameters of non-mining walls in an open pit mine 385–640 m deep, with overall slope angles of 38–55° and a steeper H 0.35–0.5 lower part having the slope angle of up to 70° with average strength characteristics of 7.85–11.84 MPa and the internal friction angle of 28.1–37.4°. Using the natural load-bearing capacity of rock mass to the full advantage, which the values of the structural relaxation coefficient of deposits show, allows optimization of open pit wall slope design and minimization of stripping operations.

scholarly journals Partial Replacement of Cement by Neem Leaves Ash and Fly Ash

2020 ◽  
Vol 9 (1) ◽  
pp. 506-508
Keyword(s):  
Experimental Investigation ◽  
Fly Ash ◽  
Ordinary Portland Cement ◽  
Construction Materials ◽  
Strength Properties ◽  
Vital Role ◽  
Partial Replacement ◽  
Cement Ratio ◽  
Neem Leaves ◽  
The World

Concrete is the most essential construction materials in all over the world. It is necessary to search the cheaply obtainable material as admixture which might be partially replaced cement in the production of concrete. This project is an experimental investigation of the neem leaves ash as partial replacement for cement also fly ash is used for partial replacement of cement. The neem leaves were dried, burnt and heated in the furnace to produce Neem leaves Ash, which was discovered to posses Pozzolanic properties.the ordinary Portland cement was replaced by neem ash by 5%,10%,15%,20% and 25% by weight also flash replaced by 15%,20%,25% and 30% the cubes were crushed to know the comparative strength of the concrete at different curing days. The last result showed that workability and strength properties of the concrete was depended on water cement ratio, total days of curing, the percentage of replacement of Neem leaves ash for OPC . I. This project it was noticed that the result of 5% NLA and 15% fly ash and 10% NLA and 20% of fly ash were gradually increasing the strength at 28 days. Neem leaves play a vital role and behaviour of Neem leaves ash and flash used concrete will be studied

scholarly journals Assessment of Workability and Compressive Strength of Rice Husk Ash-Blended Palm Kernel Shell Concrete

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
K. O. Oriola
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Construction Materials ◽  
Palm Kernel ◽  
Lightweight Aggregate ◽  
Strength Properties ◽  
Lightweight Aggregate Concrete ◽  
Palm Kernel Shell ◽  
Compressive Strength Of Concrete

The evaluation of agro-industrial by-products as alternative construction materials is becoming more significant as the demand for environmentally friendly construction materials increases. In this study, the workability and compressive strength of concrete produced by combining Palm Kernel Shell (PKS) and Rice Husk Ash (RHA) was investigated. Concrete mixes using a fixed content of 15% RHA as replacement for cement and 20, 40, 60, 80 and 100% PKS as replacement for crushed granite by volume with the mix ratios of 1:1½:3, 1:2:4 and 1:3:6 were produced. The water-to-cement ratios of 0.5, 0.6 and 0.7 were used for the respective mix ratios. Concrete without PKS and RHA served as control mix. The fresh concrete workability was evaluated through slump test. The concrete hardened properties determined were the density and compressive strength. The results indicated that the workability and density of PKSC were lower than control concrete, and they decreased as the PKS content in each mix ratio was increased. The compressive strength of concrete at 90 days decreased from 27.8-13.1 N/mm2, 23.8-8.9 N/mm2and 20.6-7.6 for 1:1½:3, 1:2:4 and 1:3:6, respectively as the substitution level of PKS increased from 0-100%. However, the compressive strength of concrete increased with curing age and the gain in strength of concrete containing RHA and PKSC were higher than the control at the later age. The concrete containing 15% RHA with up to 40% PKS for 1:1½:3 and 20% PKS for 1:2:4 mix ratios satisfied the minimum strength requirements for structural lightweight aggregate concrete (SLWAC) stipulated by the relevant standards. It can be concluded that the addition of 15% RHA is effective in improving the strength properties of PKSC for eco-friendly SLWAC production..

Changes of Mechanical Properties in Response to Changes in the Microstructure of High Pressure Steel Cylinders Obtained by the Various Heat Treatments

2014 ◽  
Vol 782 ◽  
pp. 191-196
Author(s):  
Pavel Kučera ◽  
Eva Mazancová
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Automotive Industry ◽  
Conventional Treatment ◽  
Strength Properties ◽  
Compressed Natural Gas ◽  
New Techniques ◽  
Safety Requirements ◽  
Notch Impact Strength

The field of high-pressure steel cylinders (HPSC) and vessels used for the variety of applications especially for the CNG (Compressed Natural Gas) in automotive industry is still expanding. With increasing safety requirements, a need of new techniques applied in field of HPSC structural innovations comes into place. Conventional treatment provides generally sufficient parameters of HPSC, but the long-term goal is to achieve as high as possible strength properties vs. as high as possible notch impact strength, which is currently difficult fully accessible, because of the banded structures (segregation banding) created during the process of reversed extrusion and reversed hot rolling.

Assessment of the technical condition of mines with mechanical fuses

2021 ◽  
Vol 2021 (1) ◽  
pp. 1-12
Author(s):  
Adam Kubecki ◽  
Cezary Śliwiński ◽  
Janusz Śliwiński ◽  
Ireneusz Lubach ◽  
Leszek Bogdan ◽  
...  
Keyword(s):  
Construction Materials ◽  
Armed Forces ◽  
Operational Reliability ◽  
Strength Properties ◽  
Technical Condition ◽  
Armed Conflicts ◽  
Long Term Storage ◽  
Precise Adjustment ◽  
Main Charge ◽  
Materials Used

Contemporary armed conflicts reveal that the use of effective mine barriers has a significant impact on the course of hostilities. Therefore, the Polish Armed Forces selected reliable and effective explosive ordnance as a priority, both newly-acquired material and those currently in operation. For this reason, among others, strict supervision over the technical condition of mines is exercised, in particular during their long-term storage. The reasons behind the increased mine unreliability may include physical and chemical changes in the construction materials used (corrosion, deformations, loss of strength properties), deterioration of the physicochemical properties of the main charge, booster and primer-detonator, inadequate technical condition of the safety components, or the failure of mine fuse mechanisms. In order to assess the mine's operational reliability, each mine fuse subassembly is examined and then a check of the entire assembled mine is performed. This requires proper planning of the full test cycle and the use of inspected and calibrated measuring devices and test stands enabling the precise adjustment of mechanical and climatic stress parameters.

Strength Properties and Microscopic Observations of Concrete with Plastic Wastes as Partial Aggregate Substitute

2018 ◽  
Author(s):  
Andres Winston C. Oreta ◽  
Maejann E. Cuartero ◽  
Nikko Paolo P. Villanueva
Keyword(s):  
Low Cost ◽  
Construction Materials ◽  
Strength Properties ◽  
The Philippines ◽  
Sustainable Construction ◽  
Strength Performance ◽  
Plastic Bags ◽  
Plastic Wastes ◽  
Metro Manila ◽  
Performance Results

<p>Sustainable construction can be promoted by producing construction materials with recycled waste. This study aims to address the issue of recycling plastic wastes and providing a means of livelihood in a relocation site of typhoon victims and urban settlers in Metro Manila by exploring the production of quality concrete hollow blocks (CHB) mixed with waste plastic wastes. In the study, the strength properties of concrete with various types of plastic wastes (PW) such as plastic bags (PB) and noodle wrappers (NW) as substitute to fine aggregates were investigated. Different percent substitutions, specifically 2.5%, 5%, 7.5% and 10%, were considered for each mix. The behaviour and strength properties of the concrete with and without PW were analysed and compared Moreover, the microscopic structures of the various types of mixes were observed using a Scanning Electron Microscopy (SEM) and related to the failure mode and strength performance. Results show that concrete with PB outperformed the other concrete mixes with plastics due to the plastic bag’s high stretchable property, compared to the noodle wrappers. In addition, plastics, in general, provide additional ductility to the concrete enabling them to tolerate more deformation at lower loads. The final product of the study is a mix design for producing non-load bearing concrete hollow blocks (CHB) that can be used for low-cost housing in the Philippines.</p>

scholarly journals Structural Characteristics of Developed Sustainable Lime-Straw Composite

2019 ◽  
Vol 5 (12) ◽  
pp. 2587-2597
Author(s):  
Sajid Kamil Zemam ◽  
Sa'ad Fahad Resan ◽  
Musab Sabah Abed
Keyword(s):  
Structural Characteristics ◽  
Low Cost ◽  
Construction Material ◽  
Construction Materials ◽  
Strength Properties ◽  
Sustainable Construction ◽  
Unit Weight ◽  
Experimental Program ◽  
Hemp Fiber ◽  
Environmental Friendliness

Construction materials made of renewable resources have promising potential given their low cost, availability, and environmental friendliness. Although hemp fibers are the most extensively used fiber in the eco-friendly building sector, their unavailability hinders their application in Iraq. This study aimed to overcome the absence of hemp fiber in Iraq and develop a new sustainable construction material, strawcrete, by using wheat straw and traditional lime as the base binder. A comparable method of developing hempcrete was established. The experimental program adopted novel Mixing Sequence Techniques (MSTs), which depended on changing the sequence of mixed material with fixed proportions. The orientation of the applied load and the specimen’s aspect ratio were also studied. The mixing proportion was 4:1:1 (fiber/binder/water) by volume. Results showed that the developed strawcrete had a dry unit weight ranging from 645 kg/m3 to 734 kg/m3 and a compressive strength ranging from 1.8 MPa to 3.8 MPa. The enhanced physical and strength properties varied with the MST and loading orientation. The properties of the developed hempcrete were compared with those of strawcrete.

scholarly journals SPECIFIC ASSESSMENT OF FINE AGGREGATES FROM DIBDIBBA FORMATION AT TAR AL-SAYED IN KARBALA (MIDDLE OF IRAQ) AS CONSTRUCTION MATERIALS

2020 ◽  
Vol 53 (2D) ◽  
pp. 94-106
Author(s):  
khaled Alhadad
Keyword(s):  
Grain Size ◽  
Construction Materials ◽  
Total Dissolved Solids ◽  
Fine Aggregate ◽  
Global Standards ◽  
Fine Aggregates ◽  
Gypsum Content ◽  
Specific Assessment ◽  
Physical Tests ◽  
Construction Works

This research deals with assessing fine aggregate (sand) properties as construction materials, that were collected from the Dibdibba Formation at Tar AL-Sayed, Karbala, Iraq, in mortar, concrete, tiles, thermo-stone, solid, hollow masonry blocks and cement paste. Physical tests were carried out on five samples, the moisture content, specific gravity, density of both bulk, dry and porosity were almost varied. The tested samples show that they are unsuitable for all types of concrete, tiles types, thermo-stone and cement masonry block in terms of grain size in all fractions except that of 4.75 mm and 2.36 mm. Later all samples were treated by washing using fresh water, fine clean sand was added in an attempt to form a convenient type for all construction works. The total dissolved solids (1.67– 4.53%), gypsum content (0.64–2.13%), organic matters (0.71 – 2.01%), Cl- (0.11 – 0.81%) and pH (7.51 – 7.91) are ranged within the global standards (ASTM, USCS, BS, and IQS). Quartz is predominated mineral, albite and gypsum are of moderate abundance, whereas mica and calcite occurred as traces.

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