scholarly journals Impact of Drying and Wetting Cycles on Vegetation Cement-soil Physical and Mechanical Properties

Author(s):  
Xudong Hu ◽  
Jiazhen Gao ◽  
Mingtao Zhou ◽  
Songtao Peng ◽  
Wennian Xu ◽  
...  

The physical and mechanical properties of the ecological slope protection substrate will be affected by long-term variation of the meteorological condition, resulting in the stability of the substrate being reduced. So an artificial substrate of vegetation cement-soil was selected as the research object to prepare specimens with the different initial moisture content of 13%, 19%, 25%, 31%, 37%, and 43%. And a series of tests are conducted to investigate the evolution of the physical and mechanical properties under drying-wetting cycling conditions. Typical results of the vegetation cement-soil evolution can be divided into three stages: cement hydration stage, shrinkage stage, and stabilization stage. In terms of different initial moisture content, the shrinkage cracks number, cracks length, crack width, and cracks surface area are increased first and then stabilize with the increase of the number of drying-wetting cycles. In contrast, the cohesion and internal friction angle of the vegetation cement-soil is reduced with the increase of the number of cycles. Comprehensive analysis shows that the initial moisture content of vegetation cement soil ranges from 25% to 31% is the optimal choice to ensure substrate stability in production practice.

2013 ◽  
Vol 790 ◽  
pp. 306-309
Author(s):  
Hua Hu ◽  
Xiao Xu Zheng

In south China, residual soil is widely distributed and one of the most main soil in engineering construction at the coastal areas. While its mechanical characteristics are easily affected by moisture content, which is a serious threat to engineering stability and safety. In this paper, granite residual soil in a construction site of Xiamen is selected as remoulded specimens, and unconfined compressive strength test and static triaxial shear test are used, which will show the influence of moisture content (20%, 23% and 26%) on the mechanical properties of specimens. As the result is analyzed, it shows that mechanical properties such as stress-strain relationship, unconfined compression strength, internal cohesive force, internal friction angle, and shear strength, are better than other specimens when the moisture content is 23%, which will be beneficial to the stability and security of engineering soil.


Author(s):  
Agus Tugas Sudjianto ◽  
Aji Suraji ◽  
Sugeng Hadi Susilo

Expansive clay is one of the problems in construction work. The soil has the characteristics of being easy to expand when exposed to water, causing a decrease in the strength value of the soil. The can be overcome by stabilizing the soil. The soil is formed from weathering and contains the mineral montmorillonite. The soil is very sensitive to moisture content, has a high shrinkage rate, thus interfering in construction work. Therefore, additional materials are needed to overcome the problem, one of which is soil stabilization. The study aimed to stabilize the expansive clay soil. This is done by analyzing the physical and mechanical properties of expansive clay with a shell ash mixture. Expansive clay is taken directly (undisturbed) or disturbed. Undisturbed soil is taken using a tube, so that the soil is not disturbed by outside air, while disturbed soil is taken using a shovel and then put into a sack container. Expansive clay stabilization method lies in adding the percentage of shell ash mixture (5 %, 10 %, 15 %, and 20 %). The soil, the initial moisture content (γd) of which has been determined, is mixed, then molded into a cylindrical shape. The mold was stored in a desiccator, then watered with 5 % water every day until the soil became saturated. Then, using a Proctor test, chemical tests (soil chemical test, soil mineral test), physical tests (soil moisture, Atterberg limit), and mechanical tests (unconfined compression test, compaction test, swelling test) were carried out. The results showed that the addition of an oyster shell ash stabilizing agent to expansive clay affected the physical and mechanical properties of the soil. The addition of shell ash can reduce soil moisture with various plasticity indexes. While the soil stress value decreased, the swelling of the soil increased significantly above the original soil.


Author(s):  
Sujiman Kusnadi

Research was located In Teluk Pandan District, East Kutai Regency, East Kalimantan Province.  It’s aimed to determine the lithology in the  research area and to find out how the amount of slope that will be a landslide at that location. The research conducted with the analysis of coring drilling results and then analyzed in the laboratory of rock mechanics to get the characteristic of physical and mechanical properties of the rocks. The data analysis using Hoek and Bray Method. The results showed that in the area study has a sedimentary rock lithology fine to medium detritus, such as claystone, siltstone and sandstone, as well as inserts are coal and shale. Based on the results of laboratory analysis of rock mechanics obtained density between 2,648 to 2,770. While the test results obtained value triaxial cohesion between (6.66 - 9:05) Kg / cm2, friction angle in between (37.19 - 44.08)o, cohesion residual (2.72 - 3.10) Kg / cm2, residual friction angle (27.22 - 32.44)o. While the direct shear test the cohesion of the summit between (6.66 - 9:05) Kg / cm2, friction angle in the cohesion peak (36.15 - 43.00)o, cohesion residual (2:22 to 3:10) Kg / cm2, friction angle in the cohesion residual (37.22 - 33.85)o. The simulation results stability of the slope stability Hoek and Bray using rockslide software, the result is that if the slope with a single slope stability, the stability of the slope is 60o, and if the slope with the stability of the slope overall stability of the slope is 48o.


2021 ◽  
Vol 1 ◽  
pp. 17-24
Author(s):  
Abdessattar LAMAMRA ◽  
◽  
Dmitriy Leonidovich NEGURITSA ◽  
Samir BEDR ◽  
Ariant A. REKA ◽  
...  

Reserch relaevance. Most ground movements are generally due to rock instability, this natural phenomenon poses a risk to humanity. The properties of the rock mass directly influence the type of movement especially in underground structures. Research aim. Our goal is to characterize and classify the rock mass of diatomite from the sig mine using geomechanical classification systems such as the RQD and RMR in order to determine the quality of the rocks in the sig mine Western Algeria from the determination of the physical and mechanical properties. Methodology. In this article, the characterization analysis of the diatomite rock mass of the sig mine was carried out. First, determinations of the physical properties and carried out the triaxial test to determine the mechanical properties (young’s modulus, the friction angle, the dilatancy angle, the cohesion, the poisson’s ratio). Secondly to classify the deposit and give a recommendation to avoid stability problems. Research results. The results from physical and mechanical analyzes, it can be said that the nature of the rock present in the diatomite (underground mine) does not have enough resistance. Conclusion. Our study definitively proves that the rock mass of sig diatomite is of very low quality and it will be very dangerous for the underground mining work of the mine especially in places where the mineralized layer is very deep. And we suggest to replace the mining technique room and pillar currently used in the diatomite mine and put another mining method which includes roof support system to ensure the safety both of the miners and the equipment.


2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Dendi Prayoga ◽  
. Dirhamsyah ◽  
. Nurhaida

This research aimed to examine the physical and mechanical properties of particle boards based on the composition of raw materials and adhesive content and know the treatment of the composition of raw materials and the best adhesive content and meet the standard JIS A 5908-2003. The research was conducted at Wood Workshop Laboratory, Wood Processing Laboratory Faculty of Forestry,Tanjungpura University and Laboratory of PT. Duta Pertiwi Nusantara Pontianak. The adhesive used is Urea Formaldehyde with 52% Solid Content. Comparison of the composition of rice husks and sengon varies namely rice husk 50%: sengon 50%, rice husk 60%: sengon 40% and rice husk 70%: sengon 30%  and variations in the levels of UF adhesives, namely 14% and 16%, with target density 0,7 gr/cm3. The particleboard was 30 cm x 30 cm x 1 cm Pressing at temperature 140oC for 8 minutes, with  pressure of 25 kg/cm2. The research results of the study of density and moisture content meet the standards JIS A 5908-2003. The best particle values of rice husk and sengon  with composition a ratio of  rice husk 50%: sengon 50% , 16% adhesive content  16%, with density value of  0,7072 gr/cm3, moisture content 9,1949 %, thick development 12,3210 %, water absorption 68,8270 %, MOE 12110,7273 kg/cm2, MOR 161,0025 kg/cm2, firmness sticky 1,9320 kg/cm2, screw holding strength 62,3124 kg.Keywords : adhesive, composition, particle board, rice husk, sengon


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
. Erma ◽  
Fadiilah H Usman ◽  
. Muflihati

Physical and mechanical properties of wood is one of the basic properties that need to be known in the selection of wood, because the physical and mechanical properties of wood are not the same height on the stem. Increased wood demand gives the opportunity to use wood that is not yet known for its marketing, one of which is Salam wood (Syzygium polianthum (Wight) Walp). The purpose of this research was to determine the physical and mechanical properties of Salam wood based on the height of the stem so that Salam wood can be optimally utilized by testing based on Classification SNI – 5 PKKI 1961. Methods of making test and test examples based on British Standard Methods No. 373-1957. The results showed that Salam wood has physical properties with an average  brown colour, the moisture content 3,13 % , density  0,58 kg/cm2 , Depreciation 2,59 %. Salam has mechanical properties with an average height position stem from base to tip with Modulus of Elastiscity (MOE)  97.701,54 , Modulus of Rupture (MOR) 659,18  and  Modulus Crushing  Streang 342,86 . Salam can be classified into strong class III and based on its properties and mechanics, it is suitable for use as a lightweight construction and furniture.Keywords: Density, depreciation, MCS, MOE, moisture content, MOR


2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Mayang Archila ◽  
Farah Diba ◽  
Dina Setyawati ◽  
. Nurhaida

The objective of this research is to evaluate the effect of the number of composite layers on the quality of the composite board from sago bark waste and plastic waste, and the number of composite layers that produce the best quality on composite board. The composite board is made with size 30 cm x 30 cm x 1 cm. The composition and division of the material was carried out manually with the polypropylene distribution divided into three parts: the front and rear respectively of 15%, and the center 70% of the plastic weight. Target density of composite boards was 0.7 g / cm3. The treatment used is based on the number of layers composing, which is 5 layers, 7 layers, 9 layers, 11 layers and 13 layers. After mixed the sago bark particle and waste of polypropylene, the materials then compressed with hot press at 180oC with pressure about ± 25 kg / cm2 for 10 minutes. The composite boards then tested the quality included physical and mechanical properties. Testing of physical and mechanical properties refers to JIS A 5908-2003 standard. Physical properties consist of density, moisture content, thickness swelling, and water absorption. Mechanical properties consist of modulus of rupture, modulus of elasticity, internal bonding, and modulus of screw holding strength. The study used a completely randomized design experiment consisting of 5 treatments and 3 replications. The results showed the average value of composite density was range between 0.6962 – 0.7896 g/cm3, the moisture content was range between 4.3388 % - 6.8066%, the thickness swelling was range between 8.2605% - 11.9615%, and water absorption was range between 17.2380% - 22.3867%. The average value of modulus of rupture was range between 60,0632 kg/cm2 – 64,4068 kg/cm2, the modulus of elasticity was range between 17935,1813g/cm2 – 32841,8278 kg/cm2, the internal bonding was range between 1,9268 kg/cm2  - 5,4119 kg/cm2, and the modulus of screw holding strength was range between 78,2530 kg/cm2 – 92,9677 kg/cm2. The composite board made from sago stem bark waste and polypropylene waste plastic with 13 layers treatment is the best composite board and fulfilled the JIS A 5908-2003 standard. Keywords: bark of sago, composite boards, layer of composite, polypropylenes plastic, waste


Author(s):  
K. Z. Tilloev ◽  
S. V. Kondakov

The construction and method of calculating the stability of a crawler excavator equipped with a new working body (cone roller) are considered. The calculation is made on two working positions (longitudinal and transverse) of the excavator, provided that the excavator must apply the maximum force on the working body at an angle of 90°. The force applied by the excavator boom to the cone roller during the introduction depends on the physical and mechanical properties of the compacted soil. The calculation method differs in that during the compaction of the roadbed, the cone sinks into the ground, and the excavator tends to roll in the direction of the rear track support roller, in contrast to the traditional danger of tipping over the front support roller when working with a bucket.


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