scholarly journals GENERATION OF CRACKS IN HIGHWAY EMBANKMENT ON BLACK COTTON SOIL

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Yongzhen Cheng ◽  
Yun Dong ◽  
Jingke Wu ◽  
Baoliang Li ◽  
Jihua Zhang

This research revealed the crack generation of the highway embankment from the water losing shrinkage of the wet black cotton soil (BCS), which is a type of soil with high swell-shrink potential. The road seepage meter was used to test the permeability of filling materials, which was used to replace BCS. The moisture content and embankment deflection of BCS foundation were measured after the rainy season. Based on the coupled consolidation theory for unsaturated soil, the change in additional tension stress of the embankment induced by water loss shrinkage of BCS was simulated by Abaqus. The results indicated that the rainfall seeped into the foundation through highly permeable refill materials to result in BCS expansion and decrease the embankment strength. After the rainy season, the additional tensile stress caused by water loss shrinkage of BCS induces cracking of highway embankment, and the maximum cracking depth often appears at the shoulder of highway. The deep and wide cracks are easy to appear in the low embankment constructed on a thick BCS foundation under strong evaporation.

2011 ◽  
Vol 243-249 ◽  
pp. 3868-3872
Author(s):  
Lai Gui Wang ◽  
Mei Sheng Feng ◽  
Hong Zhu Zhang

For the study of soft subgrade pavement cracking process, it establishes the pavement structure tension crack model by elastic layered theory. Based on the finite element method, it studies the tension crack evolution process. It establishes the tension crack stress criterion to the roadbed. Analysis shows that the distresses of asphalt pavement of the real highway results from the damage by asymmetric sedimentation which is under excessively axle loading on pavement structure, rather than the fatigue damage by axle loading repetitions in the condition of asymmetric intensity in the same layer. The results show that the soft degree of the subgrade is proportional to the tensile stress, the more localized soft, the easier to crack the road. The soft roadbed does not have a homogeneous structure of the road surface, the tension stress rupture occurred in the discontinuous surface. The road structure has a set of tensile stress under the circulation wheel load, it formats a new fracture surface, and the structure form corresponding evolves, and causes stress state change. At last most of the road sub-base crack, and surface cracking occurres, so the pavement failure.


2017 ◽  
Vol 12 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Zhijun Liu ◽  
Dongquan Wang ◽  
Xiaobi Wei ◽  
Liangliang Wang

Cement-stabilized macadam is the most widely used road base material in road engineering. The current study investigated the impact of fiber diameter on its performance. The authors prepared polyester fibers with diameters of 20, 35, 70, and 105 μm and added them to cement-stabilized macadam. Then, the indoor shrinkage tests and mechanical property tests at different ages were conducted. Then, the property changes of the polyester-reinforced cement-stabilized macadam were analysed. The water loss rate of the polyester-reinforced cement-stabilized macadam is subject to the combined influence of the “water loss surface effect” and “water loss porthole effect.” With increasing fiber diameter, the water loss surface effect becomes stronger, and the water loss porthole effect gradually decreases; thus, the overall effect transitions from the latter to the former. Moreover, the water loss rate shows an increasing trend of decreasing to its minimum. Therefore, with increasing fiber diameter, the average dry shrinkage coefficient of the polyester-reinforced cement-stabilized macadam first increases and then decreases, while the temperature shrinkage coefficients increase. The change in the fiber diameter does not significantly affect the compressive resilient modulus of the polyester-reinforced cement-stabilized macadam if the fiber content remains constant. These findings demonstrate the functional mechanism of the fiber diameter on the road performance of cement-stabilized macadam, thus improving our understanding of the road performance of the polyester-reinforced cement-stabilized macadam and laying a solid theoretical foundation for its many applications.


2020 ◽  
Vol 13 (2) ◽  
pp. 65-79
Author(s):  
Xiong Dong ◽  
Yang Huanqiang ◽  
Liu Yang ◽  
Wang Xiaowei

Tensile stiffness of interfacial layered rock is the basis of studying the law of interlaminar propagation of hydraulic cracks. We used similar materials to make simulated specimens of sand-mud layered rock with prefabricated cracks, and used the digital image correlation (DIC) technique together with the three-point bending (TPB) test to obtain the strain field near the prefabricated crack tip in tensile state. Combined with the tensile stress in the corresponding area calculated by the load of the tester, the tensile stress-displacement curve at the interface of layered rock is obtained, and the tensile stiffness and interfacial fracture law at the interface of layered rock is calculated by the curve. The results show that in the process of tensile failure, before reaching its peak value, the interfacial tension stress of layered rock has a linear elastic deformation stage followed by a short hardening stage. Upon reaching the peak value, it is accompanied by interfacial failure and macro-cracks, and then the load decreases and enters the softening stage, which results in the complete destruction of the interface. The tensile stiffness values of layered rock with different sizes vary greatly, which indicates that the interfacial tensile stiffness values are sensitive to the specimen size and have a size effect. The results are of great significance to the study of the law of hydraulic fracture propagation in the interface of layered rock.


Africa ◽  
1949 ◽  
Vol 19 (1) ◽  
pp. 1-12 ◽  
Author(s):  
N. L. Corkill

Opening ParagraphThe village of Ulu lies at about latitude 10° N. between the White Nile and the Blue Nile in the southern part of the Fung area of the Anglo-Egyptian Sudan. The surrounding country is mostly thin savannah on black cotton soil but there are occasional outcrops of laterite as at Ulu itself. Water-holes are found and may be made in the larger watercourses after these have dried up at the termination of the rainy season. The dry season is roughly December to May. The inhabitants of Ulu call themselves Fung and are black Moslems of a possibly aboriginal stock. Wandering Araboid nomads of the Mesallamia and other tribes with camels, cattle, sheep, and goats may be encountered visiting traditional grazing areas. The Fung of Ulu cultivate millet, cow-peas and sesame seed as subsistence crops and in normal times surplus is bartered with the nomads for animals and no doubt clarified butter also. A small amount of cash is obtained by the gathering of acacia gum which is disposed of through the local Arab merchant.


Africa ◽  
1983 ◽  
Vol 53 (2) ◽  
pp. 2-23 ◽  
Author(s):  
Johan Pottier

IntroductionDuring the first few months of 1978, at the height of the rainy season, mourning lamentations hardly ever ceased at the mortuary of Mbala General Hospital. Infants and children were dying. Inadequate food intake, malabsorption of nutrients and malarial infection were the main causes of death.Those who survived the ‘hunger months’ of 1978 lived in overcrowded quarters and were fed a diet consisting mainly of diluted maize meal (‘mealie meal’) porridge. They suffered from poor dietary variation and an unprecedented shortage of basic foodstuffs. The small and isolated township of Mbala could not provide for itself; it relied on maize flour imports from the Copper belt and from Lusaka. The arrival of a truckload of flour–the road to Kasama had not yet been tarred– was sufficient to bring the town community to its feet and cause long queues of despairing people.


2020 ◽  
Vol 837 ◽  
pp. 109-115
Author(s):  
Ding Zeng ◽  
Hong Yu Lu ◽  
Bao Hong Hao ◽  
Hao Zheng Yu ◽  
Yu Mi

In order to understand the influence of the tensile stress on the corrosion of reinforcement bars in civil engineering, the reinforcement bars specimens were put into the liquid corrosion tank made of hydrochloric acid and distilled water by applying the tension stress on the reinforcing frame to carry out rapid corrosion. The corrosion of reinforcement bars under different tension stresses was tested by using electrochemical polarization method. The metallographic examination of reinforcement bars was carried out through the section of reinforcement bars. The corrosion mechanism of the stressed reinforcement bar was tested and analyzed. It can be known from the experimental study: First in the same corrosion condition, the larger the tensile stress is, the faster the corrosion of steel bar will be; Second corrosion current density or corrosion rate are index for evaluating corrosion rate of reinforcement bars with different tensile stresses. Corrosion potential can not be used as an index for evaluating corrosion rate of reinforcement bars with different tensile stresses; Third intercrystalline corrosion occurs inside the reinforcement bar due to micro-defects after rolling and moulding, which directly affects the mechanical properties of reinforcement bar.


2012 ◽  
Vol 256-259 ◽  
pp. 1866-1870
Author(s):  
Ling Yu ◽  
Jing Yang ◽  
Long Sheng Bao ◽  
Guang Shan Zhu

In order to find out the loading mechanism of Fly-Ash-Flushed-by-Seawater base asphalt pavement under heavy load and verify reasonable road pavement structure, this paper analysed the road model under different axel load with ABAQUS. The influence of structural stress and the road asphalt pavement deflection in different road structural parameters were shown in the paper. The result indicates that the structural stress and the deflection under heavy load are greater than they are under the standard load. When the vehicle is over load by 100%, the tensile stress of subbase is close to the allowable tensile stress. The structure of Fly-Ash-Flushed-by-Seawater base asphalt pavement can be designed to adapt to the over load traffic of Yingkou by adjusted the structural parameter in a certain range.


2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Koichiro Ishikawa

This study deals with partial cylindrical truss walls equipped with damper connections due to horizontal earthquake motions. The damper connection consists of an aluminum ball joint, an aluminum hub, and a steel bolt. A ductile elongation of the steel bolt due to a tensile stress is expected by avoiding the brittle collapse. The study proposes a fuse-type connection by means of yield of the steel bolt due to tension stress realized by the ductile failure collapse mechanism of the wall-type spatial structure. The proposed truss wall with the fuse-type connection can realize a deformation of nodes within the restriction for avoiding a nonstructural member damage. It is confirmed in the dynamic elastoplastic analysis that the control of the dynamic collapse mechanism such as the steel bolt elongation can avoid a brittle collapse mechanism such as a chain of member buckling. The evaluation method is also proposed by means of the limit displacement considering a ductility factor of the steel bolt within 2.0.


Author(s):  
Ardiansyah Ardiansyah ◽  
M. Gasali M.

Abstract Sungai Beringin Street is a road that has the status of a provincial road, as a connecting road between the capital city of the District of Tembilahan with other districts such as Batang Tuaka Subdistrict, Gaung Serka Children, Gaung and its surroundings. Jalan Sungai Beringin is one of the most densely populated areas of vehicle traffic experiencing flooding problems that regularly occur during the rainy season, because the condition of the drainage system is not well connected and there is no drainage channel on the road. Inundation will affect traffic for vehicles using the road to carry out daily activities, so that it can allow a greater disaster to harm the local community both property and life. According to Suripin, (2004; 7) drainage originating from English Drainage means to drain, drain, dispose of, or divert water. Drainage in the field of civil engineering, can be defined as a technical action to reduce excess water, both from rainwater, seepage, or excess irrigation water from an area / land, so that the function of the area / land is not disturbed. Drainage can also be interpreted as an effort to control the quality of groundwater in relation to salinity, so drainage involves not only surface water but also groundwater. Planning of drainage system for Parit 16 road with dimensions of channel height (h) 0.85 meters, channel width (b) 1.00 meters with slope of 0.04 and safety height of 0.65 meters while trench road 17 with high dimensions of the channel ( h) 0.95 meters, channel width (b) 1.00 meters with a slope of 0.04 and height of 0.69 meters construction of this drainage system in order to accommodate the rainwater discharge on the Beringin River which causes flood inundation during the rainy season . From the results of analysis of calculations, the total cost of the Budget Plan is obtained. The cost of constructing the ditch 16 drainage channel is = Rp. 3,219,594,000.00 and drainage ditch 17 drainage channel = Rp. 3,859,080,000.00.   Abstrak Jalan Sungai Beringin adalah jalan yang berstatus jalan Propinsi, sebagai jalan penghubung antara Ibu Kota Kabupaten Kecamatan Tembilahan dengan Kecamatan lain seperti Kecamatan Batang Tuaka, Gaung Anak Serka, Gaung dan sekitarnya. Jalan Sungai Beringin merupakan salah satu wilayah jalan lalu lintas kendaraan yang cukup padat mengalami masalah banjir genangan air yang rutin terjadi pada saat musim hujan, dikarenakan kondisi sistem drainase belum terhubung dengan baik dan tidak adanya saluran drainase pada ruas jalan tersebut. Genangan akan mengangu lalu lintas bagi kendaraan yang mengunakan ruas jalan tersebut untuk melakukan aktivitas sehari-hari, maka dapat memungkinkan terjadi bencana yang lebih besar hingga merugikan masyarakat setempat baik harta benda maupun nyawa. Menurut Suripin, (2004; 7) drainase yang berasal dari bahasa Inggris Drainage mempunyai arti mengalirkan, menguras, membuang, atau mengalihkan air. Drainase dalam bidang teknik sipil, dapat didefinisikan sebagai suatu tindakan teknis untuk mengurangi kelebihan air, baik yang berasal dari air hujan, rembesan, maupun kelebihan air irigasi dari suatu kawasan/lahan, sehingga fungsi kawasan/lahan tidak terganggu. Drainase dapat juga diartikan sebagai usaha untuk mengontrol kualitas air tanah dalam kaitannya dengan salinitas, jadi drainase menyangkut tidak hanya air permukaan tapi juga air tanah. Perencanaan sistem drainase ruas jalan Parit 16 dengan dimensi tinggi saluran (h) 0,85 meter, lebar saluran (b) 1,00 meter dengan kemiringan 0,04 dan tinggi jagaan 0,65 meter sedangkan ruas jalan parit 17 dengan dimensi tinggi saluran (h) 0,95 meter, lebar saluran (b) 1,00 meter dengan kemiringan 0,04 dan tinggi jagaan 0,69 meter pembangunan sistem drainase ini agar dapat menampung debit air hujan di jalan Sungai Beringin yang menyebabkan banjir genangan pada saat musim hujan. Dari hasil analisa perhitungan maka diperoleh total biaya Rencana Anggaran Biaya pembangunan saluran drainase ruas jalan parit 16 sebesar = Rp. 3,219,594,000.00 dan saluran drainase ruas jalan parit 17 sebesar = Rp. 3,859,080,000.00.  


2019 ◽  
Vol 11 (7) ◽  
pp. 13868-13874
Author(s):  
Shankerappa Shantveerappa Hatti ◽  
Heena Mubeen

The road passing from Kalaburagi to Chincholi in Karnataka, India, is around 70km and is a state highway having different types of moderately thick vegetation on either side. The animals utilizing this vegetation face huge threats from vehicular traffic, as was observed in recent years. Although this road does not have heavy traffic, there are significant numbers of roadkills. This study was conducted from February 2015 to January 2016. During the one-year period of the study, the mean frequency of heavy vehicles was 154 per day. Among the 283 roadkills recorded, 52 individuals belonged to the class Amphibia, constituting 18.37% of the total roadkills; no amphibian was killed in the summer season whereas 35 and 17 individuals were killed in the rainy season and in the winter season, respectively. Fifty-two individuals belonged to the class Reptilia, constituting 18.37% of the total roadkills; on an average, 10±5.8 individuals were killed in the summer season, 2.5±0.71 in the rainy season, and 3.5±2.12 in the winter season. Sixty-one individuals belonged to the class Aves, constituting 21.55% of the total roadkills; on an average, 5.71±3.03 individuals were killed in the summer season, 2.66±2.08 in the rainy season, and 4.33±3.51 in the winter season. One-hundred-and-eighteen individuals belonged to the class Mammalia, which was the most affected among the roadkills, constituting 41.69% of the total roadkills; on an average, 5.33±5.08 individuals were killed in the summer season, 5±3.9 in the rainy season, and 4.6±2.7 in the winter season. Under the IUCN Red List category, the majority of the species in this study are considered Least Concern and some of them are not even mentioned. The present study helps to know the problems and threats faced by wild animals and is the first work carried out in the region.


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