Seismic designs and numerical analyses required fundamental parameters such as damping ratio and shear modulus. In this study, large-scale triaxial cyclic tests were used to investigate the dynamic properties of limestone ballast and electric arc furnace (EAF) slag ballast. The term ‘shear stiffness’ is typically reported in a normalized form using shear modulus. As the laboratory test results showed, an increase in confining pressure, loading frequency and anisotropy raises the shear modulus of materials. Shear modulus and damping ratio values do not appear to be significantly affected by an increase in loading cycles. Loading frequency plays the most significant role in changing damping ratio values. An adaptive neuro-fuzzy inference system (ANFIS) was also used to predict the normalized shear modulus and the damping ratio in this study. The results of the developed model were consistent with those of the laboratory tests. Moreover, the relations among the dynamic properties were estimatedly determined using the nonlinear regression method.

The use of tire-derived aggregates (TDA) in railway infrastructure has gained significant attention in recent years due to its potential benefits, including vibration mitigation, ballast degradation reduction, increased damping, decreased stiffness, and improved dynamic performance of bridges. However, one major concern regarding the use of TDA-ballast mixes is the potential for increased settlement, primarily due to the softer nature of rubber particles. Hence, investigating the effect of TDA content and size on track settlement and identifying the optimal mix configuration is of critical importance. This study evaluates these effects through a series of laboratory ballast box tests conducted on different mixtures. The experimental program included pure ballast samples (as control) and ballast-TDA mixes with 5%, 10%, 15%, and 20% TDA by weight. Two TDA size ranges were considered: fine particles (10–20 mm diameter) and coarse particles (comparable to ballast size). The results revealed that, except for the mix with 10% coarse TDA—which exhibited a 1.7% reduction in settlement compared to the control—all other mixes (with 5%, 15%, and 20% coarse TDA) experienced increased settlement by 24%, 155%, and 217%, respectively. Furthermore, settlement increased significantly with rising TDA content in mixes using fine particles. Specifically, the increases in settlement for 5%, 10%, 15%, and 20% fine TDA mixes, compared to the pure ballast sample, were 22%, 88%, 234%, and 310%, respectively. Based on the results, the mix with 10% coarse TDA is recommended as the optimal configuration, offering improved long-term performance without compromising stability. These findings provide valuable insight for the design and optimization of ballast–TDA mixes, facilitating the effective integration of recycled materials in railway tracks while mitigating long-term settlement issues.

The growth of railway lines has caused engineers to seek to increase the efficiency of the ballasted railway track, and for this reason, they are looking for an increase in the maintenance intervals and a lower life cycle cost. In high-speed railways and lines with high traffic volume, especially railways with stiff and soft subgrade, the issue of line settlement is one of the challenging factors. According to the methods introduced to strengthen the subgrade so far, the use of geogrid is one of the conventional methods to reduce settlement and maintenance operations, which today requires more investigation in its optimal selection. In this article, an attempt has been made to investigate the effectiveness of geogrid to reduce stresses on the subgrade, sub-ballast layer, and ballast layer, and to explain how to choose it based on the technical parameters. In this study, the types of geogrid and the effect of mesh size, applied stress, and its effect on soil resistance have been investigated and the method of achieving the appropriate selection of geogrid has been suggested. Studies show that by using geogrid, the vertical settlement and horizontal movement of the railway panel can be reduced by 70%.

Post-Cyclic Monotonic Behavior of Steel Slags Materials Modified By Geogrid and Tire Chips As Railway Ballast and Sub Ballast

In the present study utilizing large scale direct shear test, the effect of ballast encasing with geogrid has been investigated. In this mater two ballast grading of 1 and 4 have been considered in conjunction with three types of geogrids GP35/35, GP40/20 and GP60/20. All direct shear test have been carried out under the vertical surcharges of50, 100 and 150 kPa with shear deformation rate of 1mm/min. The outcomes of the results reveals that in absence of geogrid encasing, the shear strength of ballast depends on the maximum particle size, uniformity coefficient and the vertical surcharge value. In the case of geogrid encasing of the ballast has promoted the shear strength behavior whereas for the grade 1 gradation of the ballast, the maximum friction angle corresponding to 50 and 150 kPa surcharges have been 74.5 and 68.96 degrees while the maximum reduction percentage in dilation angle has been 32.22. On the other hand for ballast grading 4, the mentioned variations have been correspondingly obtained as 30.12, 14.67 and 27.86 percentages.

In developing countries, the main question so stable is why citizens have been excluded from construction plans and which factors have deprived them from their citizen rights?The response to this question is simple and recusant: political economoy of these countries has been planned in a way that this fundamental question is less discussed. Manuel Castle attends truly to the abstruse relationship of urban classes and subject of of power. His concept in this context is an altered concept from Pareto thesis that said '' a position which anybody can't without aggravate another person achive to is the better position.''Therefore, only with true perception of the social organization relationships, understanding and analysis of flow capital, information, inequality, migration, poverty reproduction, social threats , in them material base( cities), is possible . Squatter settlement is the eventual dimension of flows that incentive unstability in urban and region scale. This research deals with the economic and social variables and those special impact among urban poverty and Squatter settlement.

Background: Invasion by different kinds of ballast water microorganisms is one of the most important marine environment problems around the world; therefore preventing the invasion of these unwanted and harmful stowaways is one of the main strategies of responsible agencies. Some of these methods such as ocean exchange, heating, filtration, hydro cyclones, UV irradiation and chemical treatment, have various problems such as technical deficiency, high costs, lack of safety and environmental side effects. Materials and Methods: A novel system of treatment by Gamma irradiation is designed to irradiate the blast water uniformly and effectively. To determine the dose distribution as a function of distance from the irradiation source, the MNCP code was used. The systems used for source implant in this simulation were Paterson-Parker, Paris and Network systems. In each system, Sivert-integral and inverse square law were used in MATLAB program to determine the dose distribution. Results: Results of initial laboratory tests on offshore water samples of Siri Island indicated that the appropriate dose for deactivation of organisms of water samples is approximately one kGy. It has been demonstrated that the dose can be provided by twenty five 100,000 Ci line sources of 60Co in a triangle implant arranged in a 1x1 x1 m3 cubic shape water pipe. In order to increase efficiency and radiation safety, water passed from two other coaxial and bigger cubes, after passing from the first cube. A one meter thick wall of concrete around the cubes was adequate to shield the system completely. Conclusion: The main advantages of this system such as high efficiency, safety, reliability, minimum environmental adverse effects, prove that this novel method not only can be used for ballast water treatment, but is also effective for drinking water purification.

Ballast is a layer between sleeper and sub-ballast that is composed of broken stones. Since ballast bears heavy loads, its high quality is important. If the ballast is gradually crushed and fines are generated, stone permeability and drainage property will be damaged and finally, instability will be resulted. If the above problems occur at ballast, its substitution is necessary that has high costs. For Ballast quality control several tests has been suggested in 301 railway magazine that after the test on Ballast, the results are compared with allowable values and Ballast quality was controlled. Ballast grains subjected to train loads, contain numerous cracks. From the fracture mechanic point of view, when stress intensity factor at the crack tip reaches the mixed-mode fracture toughness, crack growth begins and Ballast grains crush. Ballast crushing and abrasion are the main reasons for ballast contamination which is the main source of various defects, particularly geometric defects in the railway. Since disc-type specimens are among favorite test samples for determining mode I and mixed mode fracture toughness in brittle materials like rocks, Therefore it is suggested to add the determination of the mixed-mode fracture toughness I and II with the semi-circular bend specimens subjected to three-point-bend loading to the ballast quality control in 301 railway magazine. In this research, discussed the importance of fracture toughness in extraction, crushing and operation of Ballast, then the finite element method and experimental is used to analyze a semi-circular disc specimens under bending load and the fracture toughness of two Ballast mine, Anjilavand and Gaduk was determined. Anjilavand and Gaduk mine is two Ballast mines in Iran that using them for Ballast layers in railway substructure. The crack parameters KI, KII and T are calculated for different mixed-mode from pure mode I to pure mode II. YI, YII, and T* are the non-dimensional forms of KI, KII, and T, respectively. These parameters are functions of the crack length ratio, the crack angle and also the location of loading supports in the semi-circular bend specimen. The curves of YI, YII, and T* extracted for various combinations of modes I and II. Since the results for mixed mode fracture resistance of brittle materials are usually presented in a normalized form as KII/KIc versus KI/KIc, where KIc is a material constant called the pure mode I fracture toughness, using the mixed-mode fracture criteria, capped failure modes I and II for both ballast rocks were extracted and compared. Fracture toughness of Anjilacvand specimen is greater than Gaduk specimen that shows the Anjilavand Ballast for operation in railway is better than Gaduk Ballast.

The influence of main quality tests on the overall quality of railway ballast materials is assessed in this study. The need to integrate all acceptance tests in a unified manner for precise evaluation of ballast quality is identified, and a technique of performing this is proposed. Using this approach, a new ballast quality index (BQI) is defined in which, the main acceptance tests including abrasive strength, abrasive hardness, fragmentation strength under external loads and weathering resistance, are considered. For the development of the new BQI, all tests results are combined, assigning justified coefficients to each test value according to its contribution on overall quality. Moreover, the comparison of the new index versus the Abrasion Number (AN) as a proposed approach of the Canadian Pacific Railroad for ballast selection is investigated. A practical use of the new index is finally presented with regard to the laboratory investigations on different ballast rocks, to indicate its capability and applicability.