Permeable Blocks Research Articles

Analysis of Infiltration and Runoff Based on the Volume of Storage Spaces in Storage Permeable Blocks

Recent climate change has led to an increase in total rainfall in spite of a decrease in the number of rainy days. In addition, the increase in impervious surfaces due to urbanization has resulted in greater surface runoff, resulting in urban flooding and flash floods. To address this issue, low-impact development techniques have been introduced to improve water cycle health within watersheds. Permeable pavements, which serve as roadways while reducing impervious surfaces, have been introduced in new towns and development zones. However, most performance evaluations were based solely on the permeability coefficient of the pavement, with limited research on the water cycle performance of the entire permeable pavement system, including the subbase layer. Therefore, this study aims to analyze the effects of the porosity storage volume of joint-type permeable blocks with storage spaces under the same conditions for two types of permeable blocks. The results showed that increasing the porosity storage volume reduced the equilibrium runoff rate by 70%, and increased the runoff time delay by 2 to 2.5 times.

Interlocking Elements to Control Erosion in Natural and Urban Ecosystems

Advancements in comprehending soil erosion alleviation, relevant to both natural terrains and urban settings, have experienced notable growth in knowledge and products. Nevertheless, the increasing influence of climate change-driven forces, extreme weather events, and human-caused actions have resulted in reduced attainment of the desired results in erosion mitigation efforts. This paper aims to investigate how interlocking elements contribute to the reduction of soil erosion in natural landscapes and urban green spaces. This will be achieved by analyzing published materials, patents, installation instructions, manuals, and reports from organizations. Furthermore, we delve into novel interlocking products and emerging strategies like soft solutions and ecologically engineered blocks designed to effectively address soil erosion within vegetated habitats while enhancing the system’s capacity to adapt and withstand shifts in climate, curbing soil loss, and diminishing the speed of water runoff, consequently mitigating the potential for erosion. Geotechnical engineering and other erosion control solutions like biobased interlocking components and interlocking permeable blocks offer promise in safeguarding natural landscapes and urban infrastructure from erosion-related impacts. The geotextiles market, for instance, which was valued at over $7 billion in 2022, is anticipated to experience an annual growth rate of 6.6% from 2023 to 2030. This growth can be attributed to increasing environmental concerns related to soil erosion and the rapid urbanization occurring in developing countries. However, continuous progress in the economic viability and sustainability of these techniques and products is crucial to effectively achieve erosion mitigation goals in the face of a shifting climate.

Permeable Blocks with Waste Glass as Coarse Aggregate

In order to reduce the negative impact of waste glass and urban heat on the environment, this research aims to use waste glass cullet as an aggregate in concrete paving blocks. This work aims to produce porous pavement using two sizes of waste glass and ordinary Portland cement (OPC). Two layers of paving blocks with different aggregate sizes were planned. The first part of the work was to determine the best OPC content. The results showed that the largest aggregate-based porous paving block had the highest compressive strength and acceptable permeability. Then, designed porous block (DPB) was designed, which consisted of two layers, with the upper layer consisting of small aggregates and the lower layer consisting of large aggregates, and cement mortar (80 wt% cement powder and 20 wt% glass powder) was used as the binder. Compressive strength and permeability were the criteria. The pavement can release heat better than conventional pavements and is safe because of the skid resistance, which meets the criteria.

Analysis of the Permeability Effects of Permeable Blocks for Sidewalks and Roadways with Periods

Analysis of the Permeability Effects of Permeable Blocks for Sidewalks and Roadways with Periods

Actual NOX and SOX removal rates in the atmospheric environment of concrete permeable blocks containing TiO2 powders, coconut shell powders, and zeolite beads

Actual NOX and SOX removal rates in the atmospheric environment of concrete permeable blocks containing TiO2 powders, coconut shell powders, and zeolite beads

Baffles’ size impact on the heat transfer and second law features of magnetic hybrid nanofluid within a hexagonal-shaped porous domain

Baffles’ size impact on the heat transfer and second law features of magnetic hybrid nanofluid within a hexagonal-shaped porous domain

Variable Magnetic Field Effect on Non-Newtonian Nanofluid Convective Flow in a Channel Containing Heated Permeable Blocks

Variable Magnetic Field Effect on Non-Newtonian Nanofluid Convective Flow in a Channel Containing Heated Permeable Blocks

Numerical modeling of fluid flow through multiscale fractured-porous media by quadtrees

A multiscale fractured-porous medium has several hierarchical levels of heterogeneity and consists of a connected network of fractures and a periodic system of low permeable blocks. Each of them also consists of smaller fractures and smaller blocks. Repeating this procedure n times, we obtain a fractured-porous medium with n scales. Numerical simulation of fluid flow in such a medium is impossible due to the need to use a very fine numerical grid. To reduce the number of numerical cells, we suggest using irregular grids based on quadtree technology. We simulated numerically an example of flow in a four-scale medium and compared it with the results obtained using regular grids, as well as with the averaged process model. We have introduced a quantitative criterion that enables us to identify which cells should be refined and which should not. This gave us the opportunity to formalize the procedure for building a quadtree and embed it in the Basilisk platform. • Multiscale media require huge CPU-memory, which can be reduced by 60% by quadtrees. • The 2D problem of flow in three- and four-scale media has been solved by quadtrees. • The averaged integro-differential model has been also solved, by numerical Laplace transform. • Good convergence of the quadtree solution to the averaged model. • Flow in four-scale media has been simulated for the first time.

Development of Environment Friendly Permeable Concrete Bio Blocks

Development of Environment Friendly Permeable Concrete Bio Blocks

Permeable Coastal Pavement Structure for Shore Protection and Removal of Non-point Source Pollutants

Due to climate change, coastal areas are being flooded with torrential rain, typhoons, and tsunamis. In addition, non-point source pollutants (NPSs) that accumulated on the ground, streets, and buildings during the dry season are washed off by rain and stormwater runoff, which adds to the damage associated with environmental pollution, e.g., pollution that makes its way into the ocean. Recently, low impact development (LID) has been considered as a means of controlling water circulation and NPSs. In the coastal area, permeable blocks have been constructed mainly to reduce the flood damage caused by waves. Some important design factors that must be considered to ensure long-term performance are the permeability coefficient, clogging, and the efficiency of the removal of total suspended solids (TSS), but currently there are no standardized design criteria or testing techniques that are used worldwide. Herein, we analyzed the permeability coefficient and the TSS removal efficiency tendency according to the permeability area ratio with an easily-detachable, permeable block filled with calcinated yellow soils as the filter media. Our lab-scale tests indicated that, when the permeability area ratio was 25%, the reduction of the permeability coefficient after clogged was 11%, which was a significant decrease compared to other cases. Permeability persistence increased when the permeability area ratio increased from 50% to 75%. The TSS removal efficiency decreased as the permeability area ratio increased. Our pilot-scale test indicated that the TSS removal efficiency was more than 80% higher in all cases. We also found that the permeability persistence was excellent as the permeability area ratio increased, and, in actual construction, it is effective to set 5.3% of the total area as permeable area in terms of permeability and economic feasibility.

ACCOUNTING OF SORPTION IN THE DIFFUSION MODELING IN ROCKS OF LOW-PERMEABILITY

The main reservoir for multicomponent industrial effluents entering the geological environment is the porous space of weakly permeable blocks of rocks.The flow of components of industrial wastes from permeable cracks or layers into a block occurs by diffusion together with the mass exchange of the liquid and solid phases due to ion exchange and the dissolution/precipitation of minerals. The most popular mass exchange model for the migration forecast is a linear sorption isotherm, where the main parameter is the distribution coefficient between the phases (K d ). In this paper we analyze the applying of this approach to complex models that take into account the multicomponent composition of the waste. The driving force of diffusion is the gradient of electrochemical potential. The first relatively simple model includes the dominant salt, and the salt of the microcomponent, whose cation can form complexes with the anion and be sorbed according to the Henry isotherm. Our second model of ion diffusion takes into account complex formation, cation exchange and interaction with minerals. The results of these models are compared with the analytical solution with a constant distribution coefficient. Liquid radioactive wastes with dangerous microcomponents, radioactive cesium and strontium, were chosen for the study. At the same time, stable isotopes of cesium and strontium exist in natural groundwater. We use the conditions of two sites of the radioactive waste disposal. The sites are chosen by the prevailing components of the composition: the waste of the first one (Siberian Chemical Works — SCW), is nitrate-sodium brine, and groundwater is fresh, the second one (Research Institute of Atomic Reactors — RIAR) has brackish waste and groundwater is chloride-sodium brine. Both models show agreement with the analytical solution (constant K d ) only for the dominant sodium nitrate. For microcomponents, cation concentrations form a maximum and anions form a minimum at the block boundary, even if the initial and boundary conditions for these components are equal. The reasons are the changing ionic strength of the solution and the change in the composition of the exchange complex. The distribution coefficient of microcomponents, calculated as the ratio of concentrations in water and rock, varies along the migration path and in time by orders of magnitude. Therefore, using of a constant Kd can lead to significant errors in the prediction of migration. However, the models of multicomponent diffusion in regional forecasts require the resource and speed of computers that far exceed the commonly used in practice studies.

Homogenized Model of Two-Phase Flow with Local Nonequilibrium in Double Porosity Media

We consider two-phase flow in a heterogeneous porous medium with highly permeable fractures and low permeable periodic blocks. The flow in the blocks is assumed to be in local capillary disequilibrium and described by Barenblatt’s relaxation relationships for the relative permeability and capillary pressure. It is shown that the homogenization of such equations leads to a new macroscopic model that includes two kinds of long-memory effects: the mass transfer between the blocks and fractures and the memory caused by the microscopic Barenblatt disequilibrium. We have obtained a general relationship for the double nonequilibrium capillary pressure which represents great interest for applications. Due to the nonlinear coupling and the nonlocality in time, the macroscopic model remains incompletely homogenized in general case. The completely homogenized model was obtained for two different regimes. The first case corresponds to a linearized flow in the blocks. In the second case, we assume a low contrast in the block-fracture permeability. Numerical results for the two-dimensional problem are presented for two test cases to demonstrate the effectiveness of the methodology.

G-20 廃棄GFRPを再利用したセラミックスの透水性ブロックおよび濾過材への応用

G-20 廃棄GFRPを再利用したセラミックスの透水性ブロックおよび濾過材への応用

Strength of water-filled permeable elastic-plastic medium under shear accompanied by compression: A theoretical study

A liquid in a pore volume influences on a strength of porous permeable media, both brittle and elastic-plastic. Despite of the dilation of the latter, a pore pressure of a liquid can remain nonzero under constrained shear loading. In the result, a liquid pressure contribute into a stress-strain state of a medium, and, correspondingly, into a strength. On the other hand, a liquid pressure depends on transportation properties of a medium namely on porosity and permeability, where the latter is determined by a characteristic diameter of filtration channels in a solid skeleton. A superposition and interplay of filtration of a liquid and its compression in pores originates a dynamical distribution of a pore pressure in a bulk of material. The non-linearity and interconnectedness of the mentioned processes clearly demonstrate the necessity of application of numerical methods for a studying of strength properties of such permeable liquid-filled media. We have studied a dependence of shear strength of a water-filled elastic-plastic sample under constrained conditions in the framework of the hybrid cellular automaton method that represents a variation of a DEM with explicit account of a liquid in pores. An elastic-plastic sample has been mounted between purely elastic permeable blocks that moved in lateral direction with a constant velocity. There were periodic boundary conditions in lateral direction. In order to create an initial hydrostatic compression in a volume, a pre-loading was performed before shearing. The elastic blocks and the sample had the same values of porosity, permeability, elastic moduli etc. We varied the values of the shear rate, the value of hydrostatic compression, width of the sample and the permeability. We have found that the strength of the sample depends on a cooperation of the following processes: 1) increase of a mean stress in a medium under shear; 2) dilation of elastic-plastic sample after reaching a yield point; 3) mass transfer of a fluid in a pore volume of a sample and elastic blocks and 4) redistribution of a fluid pressure due to its mass transfer. The observed effects together with the results of numerical simulations allowed us to suggest a binomial dependence of shear strength of an elastic-plastic sample on permeability, loading parameters and geometry of a sample. The first term of this dependence describes the exponential decrease of strength of a sample due to the decrease of effective stiffness of the elastic blocks under outflow of a liquid into an excess pore volume of a sample. Note that the latter leads to the decrease of the degree of constraint. The second term characterizes the influence of filtration on an increase of effective stiffness of the sample due to the growth of pore pressure of a liquid. This, in turn, leads to the increase of the degree of constraint of the sample. The parameters of the given dependence represent the combinations of the values of loading, width of a sample, its physical-mechanical properties, including permeability, and physical mechanical properties of a liquid.

Effect of memory accumulation in three-scale fractured-porous media

We consider the flow of low compressible liquid described by the diffusion equation, which is also identical to the conductive heat transport, in a triple porosity medium that consists of two hierarchical connected networks of thin fractures and isolated low permeable blocks between the fractures. We reveal a unique parameterization of fracture thicknesses and permeabilities that ensures the contribution of all three medium subdomains into the macroscopic behavior. Such a parameterization corresponds to a non-selfsimilar medium. In such a medium the main flow occurs through the large-scale fractures, the small fractures/fissures play the role of fluid sources for large fractures, while the porous blocks play the role of fluid sources for small fractures. The delay in flow between different sub-domains leads to the appearance of memory in the macroscopic model described by the integro-differential operators. The double delay between three scales leads to the effect of memory accumulation, in such a way that the memory kernel of the integral operators is it-self the solution of an integro-differential cell problem. For thin fractures, the memory kernels have a specific structure that corresponds to Abel’s type. The macroscopic model is obtained by means of the asymptotic two-scale homogenization applied sequentially twice. These two sequential steps are non-symmetrical. At the first scale one deals with the problem of flow in continuous network of thin fractures/fissures surrounded by blocks, but only the boundary layer in each block is perturbed. At the second step we homogenize the flow in the medium that consists of large connected fractures and averaged blocks. Each averaged block contains a lot of small fractures and small porous blocks. At this step, in contrast, the appearance of a boundary layer inside the averaged blocks is prohibited. This model is used to calculate flow around a producing well in an oil reservoir, in comparison with the double porosity medium. The qualitative difference is revealed.

투수성 블록 2층적으로 구성된 잠제의 기본설계법 연구

The focus of this study is to provide a method for determining the dimension of a submerged breakwater satisfying the target transmission performance or predicting the transmission coefficient of a given structure. This method was developed based on data analysis of the physical experiment that was carried out by using the submerged breakwater composed of double-layer permeable blocks. Two different armor blocks of Tetrapod and Triangular Pyramid Block were used in the experiment. The parameter was introduced in the analysis of the measurement data. By using the linear regression line deduced from the analysis of the experimental data, it was possible to readily predict the wave transmission coefficient irrespective different water depths at the crest of the submerged breakwater, under the condition of significant decrease in transmitted wave height due to the submerged breakwater. This method can be effectively utilized for estimating the necessary number of blocks used for the submerged breakwater as well as comparing the transmission characteristics of the submerged breakwater according to use of different armor blocks.

분리형 투수블록의 우수유출 저감 효과 분석

최근 도시지역에서 열섬현상과 도시홍수가 빈번하게 발생되고 있다. 열섬현상과 도시홍수의 발생은 도시화에 따라 건물과 도로포장으로 대표되는 불투수면적의 증가가 주요 원인으로 인식되고 있다. 이러한 문제의 해결을 위한 일환으로 투수블록의 적용을 확대하고 있지만 공용 후 급속히 공극이 막혀 투수기능이 상실되므로 이에 대한 대책이 필요한 상황이다. 본 연구에서는 투수블록의 공극 막힘 문제를 해결하기 위해 상판, 바닥체, 격자로 이루어져 내부가 빈 공간으로 구성된 투수블록을 개발하였다. 상판에 4 mm 직경의 소형 구멍을 다수 형성하여 투수와 보행을 용이하게 하고 3 mm 두께의 격자를 설치하여 내구성을 향상시켰다. 그리고 본 블록의 성능 평가를 위해 강우강도의 모사가 가능한 실험 장치를 이용하여 실내 및 실외에서 우수유출 저감 효과를 실험하였다. 실험 결과, 본 투수블록은 기존 블록에 비해 약 30% 이상 우수유출 저감 효과가 있는 것으로 확인되었다. Heat island effect and urban floods have become more frequent in urban areas. It is widely known that such phenomena are mostly attributed to an increase in impermeable surface such as buildings and road pavements by urbanization. The permeable block pavement is preferred as one solution to manage this problem, but it is reported that their drainage function is rapidly decreased by clogging in most cases. In this study, we developed permeable blocks that consist of top plate, bottom plate and grids with a hollow inside. There are small holes on the top plate that are 4 mm in diameter, which facilitates drainage, and 3 mm-thick grids make their durability better. For performance evaluation, runoff tests in both lab and site test showed that the new permeable blocks reduced stormwater runoff by more than 30% compared to the conventional blocks.

The ‘Closed/Open’ Duality in Contemporary Urban Form

One of the innumerable ways to systemise contemporary European urban projects is to analyse the urban form originates from the master-plan concept. The duality of closed and open urban situations is an excellent conceptual tool for classification. This classification helps us to recognise, understand and represent the diversity of the city, as it is present on each level of a settlement and architecture. In the case of “Solid-oriented” projects construction and emplacement of buildings are the main goals. The principle of “Solid-oriented” projects are based on two very different, still existing traditions One is the classical European closed block structure, while the other one is the Modernist open urban system. Today we can identify two new approaches combining those two traditions in different ways. Urban transparency preserves streets, the effect of enclosure, and the dominance of buildings. At the same time density is coupled with spaciousness, blocks are fractured and the environment becomes more complex even within one block. The in-between method, based on the idea of structuralism, attempts to balance the importance of mass and space and creates permeable blocks in a new open urban structure. Besides creating urban volumes or buildings in the city, there is a new type of challenge in contemporary urban design. Since the 1990's attention has shifted to cityscape, i.e. to re-interpreting and reforming open spaces. The international literature calls this un-volumetric architecture. The duality of openness and closedness also appears here. While openness seems to dominate urban situations in contemporary cities, buildings are predominantly used in a closed manner.

Parameters that control the cleanup of fractured permeable aquifers

This study develops a modeling approach for simulating and evaluating entrapped light nonaqueous-phase liquid (light NAPL-LNAPL) dissolution and transport of the solute in a fractured permeable aquifer (FPA). The term FPA refers to an aquifer made of porous blocks of high permeability that embed fractures. The fracture network is part of the domain characterized by high permeability and negligible storage. Previous studies show that sandstone aquifers often represent FPAs. The basic model developed in this study is a two-dimensional (2-D) model of permeable blocks that embed oblique equidistant fractures with constant aperture and orientation. According to this model, two major parameters govern NAPL dissolution and transport of the solute. These parameters are: 1) the dimensionless interphase mass transfer coefficient, K(f0), and 2) the mobility number, N(M0). These parameters represent measures of heterogeneity affecting flow, NAPL dissolution, and transport of the solute in the domain. The parameter K(f0) refers to the rate at which organic mass is transferred from the NAPL into the water phase. The parameter N(M0) represents the ratio of flow through the porous blocks to flow through the fracture network in regions free of entrapped NAPL. It also provides a measure of groundwater flow bypassing regions contaminated by entrapped NAPL. In regions contaminated by entrapped NAPL our simulations have often indicated very low permeability of the porous blocks, enabling a significant increase of the fracture flow at the expense of the permeable block flow. Two types of constitutive relationships also affect the rate of FPA cleanup: 1) the relationship between the saturation of the entrapped NAPL and the permeability of the porous blocks, and 2) the relationships representing effects of the entrapped NAPL saturation and the permeable block flow velocity on rates of interphase mass transfer. This study provides basic tools for evaluating the characteristics of pump-and-treat cleanup of FPAs by referring to sets of parameters and constitutive relationships typical of FPAs. The numerical simulations carried out in this study show that at high initial saturation of the entrapped NAPL, during initial stages of the FPA cleanup the contaminant concentration increases, but later it decreases. This phenomenon originates from significant groundwater bypassing the NAPL entrapped in the permeable blocks via the fracture network.

Models of permeability contrasts in subduction zone mélange: Implications for gradients in fluid fluxes, Syros and Tinos Islands, Greece

Abstract Geological and geochemical evidence from previous studies suggest limited fluid flow through the interiors of many blocks of subducted oceanic crust within meta-ultramafic or metasedimentary melange matrix on the islands of Syros and Tinos, Cyclades, Greece. This finding is provocative because metamorphic devolatilization of igneous and sedimentary rocks during subduction should have liberated substantial volumes of fluid. In an effort to address this problem, two-dimensional numerical models incorporating permeability anisotropy and devolatilization are used to investigate spatial patterns of steady-state fluid flow through subduction zone melange under high-pressure/low-temperature (HP/LT) conditions. The modeling shows that as the permeability of the melange blocks decreases relative to the melange matrix, more flow is diverted around the blocks into the matrix. The ratio of the maximum flux (in matrix) relative to the minimum flux (in blocks) increases with the permeability contrast between the matrix and the less permeable blocks. Order-of-magnitude variations in permeability produce order-of-magnitude spatial variations in fluid fluxes between block interiors and surrounding matrix; flux variations of a factor of 10 or more can be present over very short length scales (as little as meter scale). The largest fluxes are produced in the matrix adjacent to block margins lying sub-parallel to regional foliation and flow direction. Fluid–rock reaction on block margins would be greatest in these areas, leading to asymmetrical distributions of reaction progress around blocks (illustrated herein by field mapping of a melange block on Syros). However, syn-metamorphic deformation can rotate blocks and strip off reaction zones at their margins, so it is likely that reaction zone asymmetries are commonly disrupted in nature. The inferred absence of strong fluid–rock reaction within melange blocks on Syros and Tinos could reflect low permeabilities in block interiors which acted to divert flow into melange matrix. Consequently, fluxes of subduction zone fluids through the melange matrix could have easily been very large, while low permeabilities shielded block interiors from the regional flow to varying degrees.