Soil Box Research Articles

Large scale soil box test to investigate soil deformation and creep movement on slopes by Particle Image Velocimetry (PIV)

A non-invasive 2D image analysis technique referred to as Particle Image Velocimetry (PIV) is introduced as a tool to analyze soil creep movements along slopes. PIV gained importance in recent years in the field of geotechnical testing. In this paper we examined the efficiency of this method in analyzing the effect of hydraulic stresses on creep deformations due to gravity forces using model tests. A large scale soil box (L×W×H=3.0m×1.0m×1.2m) with adjustable inclination angle was constructed and experiments were carried out investigating soil response to changes in hydraulic stress state at a given slope angle. The method is considered to have a great potential to systematically analyze the interaction between hydraulic and mechanical stresses and their effect on slope stability.

논토양에 대한 K와 Ca의 동시처리가 벼의 Radiocaesium과 Radiostrontium 흡수에 미치는 영향

A radio-tracer experiment was performed in a greenhouse to investigate the effectiveness of the simultaneous application of K and Ca as a countermeasure for reducing the radiocaesium and radiostrontium uptake by rice. Paddy soil (loam of pH 6.5) in soil boxes was spiked with and , and treated with K and Ca in the forms of KCl and , respectively, at agrochemical grades before transplanting. For the seeds of the control plants, soil-to-plant transfer factors (TF, ) of and were and , respectively, whereas the corresponding values for the straws were and , respectively. The TF values of and kept decreasing as the level of the simultaneous application of K and Ca (K/Ca, ) increased up to 33.6/322 and 48.0/460, respectively. The maximum rate of the decrease was around 60% for both radionuclides. Nearly 60% reduction in the TF value of was observed even at the dosage of 33.6/322, which was considered the optimum dosage based on crop productivity as well as reduction in the radiocaesium and radiostrontium uptake by rice. The optimum dosage may depend on various factors so further experiments need to be made for many different conditions.

Laboratory Experiments on the Effect of Microtopography on Soil-Water Movement: Spatial Variability in Wetting Front Movement

The effect of microtopography on soil-water movement is a topic of interest for a range of disciplines, with experimental studies investigating the relationship between the two lacking. Laboratory experiments were conducted by simulating rainfall across packed soil surfaces to investigate the effect of microtopography on wetting front movement within experimental soil profiles. In small soil box experiments, the observed wetting fronts for soil profiles showed considerably deeper movement beneath a smooth surface than depressions for 12–60 min rainfalls. For large soil box experiments, the wetting front reached moisture sensors installed at 5 and 10 cm depths and corresponding to various rough and smooth surface features at significantly different times, with movement being most rapid beneath the smooth surface. Wetting front movement was “quicker” beneath surface peaks than depressions for the rough surface as attributed to 2D/3D unsaturated flow. This study provides valuable experimentally based insight into the effect of microtopography on soil-water movement.

Measuring Soil-structure Interaction on Laterally Loaded Piles with Digital Image Correlation

A testing system to investigate soil-structure interaction on laterally loaded piles has been developed at Lafayette College. The two-piece soil box developed for this work allows the direct or indirect loading of single or multiple pile systems. Direct loading is accomplished by attaching hydraulic rams directly to the exposed area of the piles above the soil surface. Indirect loading is accomplished by loading the top section of the two-piece soil box, transferring the load from the ram to the side of the top section of the box and then to the pile through the surrounding soil.The interaction between the piles and the soil is monitored by a variety of sensors that range from common load cells, strain gages and displacement sensors to shape acceleration arrays, sheet pressure sensors and digital image correlation. The shape acceleration array measures the displacement of the pile along its length. Sheet pressure sensors are used to record the pressure distribution of the soil/soil box interaction in front of the directly loaded piles and behind indirectly loaded piles. Digital image correlation is used to measure surface soil movement. By combining the results from the various sensors the interaction of the soil and pile can be better understood.

Electrochemical study of the corrosion rate of carbon steel in soil: Evolution with time and determination of residual corrosion rates under cathodic protection

Steel coupons were buried in soil boxes for 2.5months, with or without cathodic protection. A soil from the field was used and moistened by demineralized water or 5gL−1 Na2SO4 solution. Instantaneous corrosion rates were deduced from voltammetry experiments while average values were obtained by weight loss measurements. A detailed analysis of the polarization curves led to an estimation of residual corrosion rates (τrc) of coupons under cathodic protection. This residual phenomenon could be followed with time and it was observed that τrc decreased down to ∼10μmyr−1. Cathodic protection could be optimised with this methodology.

Polyacrylamide coated Milorganite™ and gypsum for controlling sediment and phosphorus loads

Abstract The application of polymer for controlling erosion and the associated nutrient transport has been well documented. However, comparatively less information is available on the effect of polymer application together with soil amendments. In this study, the effect of polyacrylamide (PAM) in combination with surface application of gypsum and Milorganite™ (MILwaukee ORGAnic NITtrogEn) biosolid for reducing sediment and phosphorus transport under laboratory rainfall simulations was investigated. The treatments considered were bare soil, gypsum, Milorganite™, gypsum + Milorganite™, PAM-coated gypsum and PAM-coated Milorganite™. Application rates for gypsum and Milorganite™ were 392 kg ha −1 (350 lb/acre) and 726 kg ha −1 (650 lb/acre), respectively. The PAM was coated on gypsum and Milorganite™ at an application rate of 11.2 kg ha −1 (10 lb/acre) and 22.4 kg ha −1 (20 lb/acre), respectively. Rain simulation experiments were conducted using a rainfall intensity of 6.0 cm h −1 for 1 h on a 10% slope. Surface runoff was collected continuously from each soil box over 10 min intervals and leachate was collected continuously over the 60 min simulation. The reduction in runoff or in leachate for all treatments was not significantly different from the bare soil control. The sediment loss for PAM coated Milorganite™ was reduced by 77%, when compared to bare soil. However, the sediment loss was not significantly reduced for any other treatment compared to bare soil. The PAM-coated gypsum was not effective for erosion control in our study, and there appears to be a correlation between effectiveness and prill size. However, the gypsum (coated and uncoated) contributed about half of the dissolved reactive phosphorus (DRP) export (in the runoff) compared to bare soil. The PAM-coated Milorgante™ reduced the DRP and total phosphorus (TP) export to 0.3–0.5 times that of Milorganite™ and to levels similar to bare soil. The decreased sediment and phosphorus export for the PAM-coated Milorganite™ treatment is a signal for a potential management practice for controlling erosion and nutrient transport in fertilized agricultural landscapes.

Performance Simulation Analysis and Design of the Scale Model for the Earth Pressure Balance Shield

Referring to the Earth Pressure Balance (EPB) shield with the diameter of 6.25m, a new experiment station of EPB shield is proposed, which is loaded with mechanical structure instead of traditional soil box. The structure of the experiment model is designed for the performance analysis of the EPB shield. The mechanical loading device, which is called the soil simulator, can simulate different geological environments. The soil simulator is capable of realizing three work states, such as earth balance pressure, earth under pressure, and earth over pressure. By adopting virtual prototype technology, parametric model of the shield station is established and the co-simulation scheme is determined. Besides, the kinematic analysis as well as variation principles between the displacement and driving forces of the propulsion system are obtained, which build the foundation for optimization design and control of the shield prototype.

L-Band Reflectivity of a Furrowed Soil Surface

In a combined experimental and model study, we investigated the thermal L-band signatures of a sandy soil with periodic topography (furrows) with dimensions close to the observation wavelength of 21 cm. Measurements were carried out with a radiometer mounted on a tower and aimed at a soil box with an artificially prepared furrowed soil surface. Corresponding reflectivities were derived from brightness temperature measurements performed under dry and moist conditions, with the furrow direction either along or perpendicular to the plane of incidence. Results showed that the furrows had a pronounced effect on the reflectivity, depending on the polarization of the observed radiance, the direction of the furrows, and the soil moisture. A physical reflectivity model for dielectric periodic surfaces was used to explain the soil reflectivities measured for the different furrow directions and soil-water contents. Using this model improved the agreement between the measured and modeled reflectivities considerably compared to the Fresnel reflectivities. The observed dependence of soil reflectivity on furrow orientation and soil moisture could be reproduced by the reflectivity model. The quantitative agreement with the observed reflectivities was further improved by using a simple empirical approach to consider the small-scale heterogeneity of the top soil layer.

Escherichia coli Load Reduction from Runoff by Vegetative Filter Strips: A Laboratory-Scale Study

Vegetative filter strips (VFS) are commonly used best management practices for removing contaminants from runoff. Additional research is warranted to determine their efficiency and the most appropriate metrics for predicting fecal bacteria reductions. The objective of this research was to determine VFS effectiveness in removing from runoff relative to inflow rate, infiltration capacity, and flow concentration. This research also investigated the presence of in runoff from clean water runon after diluted manure runon events. A laboratory-scale VFS soil box (200 cm long, 100 cm wide, 7.5% slope) was packed with a sandy loam soil. Ten constant-flow VFS experiments were conducted with and without vegetation (8-10 cm ryegrass [ L.]) at low (20-40 cm s), medium (40-60 cm s), and high (85-120 cm s) flow rates and for a full (100 cm) or concentrated (40 cm) VFS flow width to simulate a channelizing flow condition. Two runon events were investigated for each experimental condition: (i) diluted liquid swine manure runon and (ii) clean water runon 48 h afterward. was used as an indicator of fecal contamination and was quantified by the most probable number (MPN) technique. No concentration reductions were observed based on peak outflow concentrations, and only small concentration reductions were observed based on outflow event mean concentrations. The mass reductions ranged from 22 to 71% and were strongly correlated to infiltration or runoff reduction ( = 0.88), which was dependent on the degree of flow concentration. Little to no effect of sedimentation on transport was observed, hypothesized to be due to minimum attachment to sediment particles because the bacteria originated from manure sources. Therefore, the design of VFS for bacteria removal should be based on the infiltration capacity in the VFS and should prevent concentrated flow, which limits total infiltration. The event mean concentrations in clean water runon experiments were between 10 and 100 MPN per 100 mL; therefore, under these conditions, VFS served as a source of residual from previous runon events.

Pseudo-Static Experimental Research and Seismic Behavior Analysis on Elevated Pile Cap Foundation

The paper deals with experimental activity on 4 scale-models of elevated pile cap foundation belonging to a real bridge. The foundation was composed of 9 piles, pile cap and pier and the special soil box was built to consider soil-pile-superstructure interaction. Two specimens were strengthened by steel protective pipe at each pile top. The tests consist of cyclically imposed displacement to 4 specimens, performed in the state key laboratory for disaster reduction in civil engineering of Tongji University. According to the test result, the peak strength of strengthening specimens is about 1.77 times of the others and the ultimate displacement is 1.66 times of the original models. Additionally, the dissipated hysteric energy capability of strengthening specimens is more than 2.15 times of the others as the equivalent viscous damping ratio is reduced by 50%. Other relevant phenomena are the pinching effect of original specimens is more obvious and the hysteretic loops of reinforced specimens are more plumpness. Moreover, the failure and collapse mechanisms of the elevated pile cap foundation were summarized. Finally, the measures to enhance the aseismic capability for elevated pile cap foundation were proposed.

A laboratory study of colloid and solute transport in surface runoff on saturated soil

Colloids in surface runoff may pose risks to the ecosystems not only because some of them (e.g., pathogens) are toxic, but also because they may facilitate the transport of other contaminants. Although many studies have been conducted to explore colloid fate and transport in the environment, current understanding of colloids in surface runoff is still limited. In this study, we conducted a range of laboratory experiments to examine the transport behavior of colloids in a surface runoff system, made of a soil box packed with quartz sand with four soil drainage outlets and one surface flow outlet. A natural clay colloid (kaolinite) and a conservative chemical tracer (bromide) were applied to the system under a simulated rainfall event (64 mm/h). Effluent soil drainage and surface flow samples were collected to determine the breakthrough concentrations of bromide and kaolinite. Under the experimental conditions tested, our results showed that surface runoff dominated the transport processes. As a result, kaolinite and bromide were found more in surface flow than in soil drainage. Comparisons between the breakthrough concentrations of bromide and kaolinite showed that kaolinite had lower mobility than bromide in the subsurface flow (i.e., soil drainage), but behaved almost identical to bromide in the surface runoff. Student’s t-test confirmed the difference between kaolinite and bromide in subsurface flow (p = 0.02). Spearman’s test and linear regression analysis, however, showed a strong 1:1 correlation between kaolinite and bromide in surface runoff (p < 0.0001). Our result indicate that colloids and chemical solutes may behave similarly in overland flow on bare soils with limited drainage when surface runoff dominates the transport processes.

Slope Monitoring System at a Slope Behind an Important Cultural Asset

Rainfall-induced slope failure has been responsible for great death and destruction in Japan. This is thus a primary consideration in preserving Japan’s many cultural important temples, palaces, and similar structures, especially in the ancient capital of Kyoto, where many important cultural assets are located on hillsides and near mountains. Our objective is to construct a slope-disaster warning system using real-time field measurement data, in-situ and laboratory testing, and numerical models. We set up field monitoring on a slope behind an important cultural asset in July 2004 to measure pore-water pressure, temperature, and rainfall intensity [1]. We firstly introduce our slope-disaster warning concept and field measurement results for the slope behind the important cultural asset in Kyoto. And then we discuss the relationship of rainfall intensity, seepage behavior, and slope failure based on monitoring data and model test results using a soil box apparatus.

Effect of Transitions in the Water Table and Soil Moisture Content on the Cathodic Protection of Buried Pipelines

Buried pipelines can be subject to transitional environments due to changes in soil type or moisture content. Changes in the height of the water table, for example, will affect not only the availability of water but also the access of oxygen to the pipe surface. Transitions between different soil types will also result in different exposure conditions for different parts of the pipe. These variations can affect the distribution of potential on the pipe surface and the ability of the CP system to provide adequate protection. A combination of laboratory-scale soil box tests and field measurements on operating pipelines has been used to study the effect of varying moisture content and water level on the level of cathodic protection and on pipe-depth environmental conditions. In both laboratory tests and field trials, the degree of protection was found to depend on the availability of cathodic reactants (O2 and/or H2O). Ingress of O2 results in a positive shift in potential as more current is required to electrochemically reduce the oxidant and the pipe is less easily polarized. Under some circumstances, the ingress of water has the same effect. Although more aerobic conditions lead to more positive potentials, the pipe is not necessarily less well protected. In many dry and/or high resistivity soils, the pipe surface may well be passive because of the high interfacial pH and/or high O2 concentration.

Technical Note A New Method for Replicating Complex Microtopographic Surfaces in Laboratory Soil Box Experiments

Current laboratory methods for creating rough soil surfaces for surface runoff, infiltration, and soil erosion experiments are limited in their ability to duplicate rough surfaces with uniform soil properties (e.g., bulk density) throughout the soil profile. A new method for replicating rough soil surfaces with uniform bulk density was developed. The new method utilizes a laboratory-scale soil box and surface mold constructed with desired rough surface microtopography. For experiments, the surface mold was set on a plane parallel with the bottom of the soil box at a height governed by the desired soil profile depth. The soil box was then rotated 90, soil was incrementally packed in 5-cm layers in the void volume between the mold and the soil box, the soil box was then rotated 90 back to horizontal, and the surface mold was removed. The ability to replicate rough surface microtopography was verified by creating five rough soil surfaces using the aforementioned method, scanning the surfaces using an instantaneous-profile laser scanner to obtain high resolution DEMs, and determining their maximum ponding area (MPA) and maximum depression storage (MDS) using a Puddle Delineation (PD) program. Each surface was then evaluated by comparing the computed MDS and MPA against the actual surface mold values. The average MPA and MDS relative errors of the five surfaces from the mold surface were 1.85% and 1.86%, respectively. A separate rough surface also was packed for evaluating bulk density of the packed soil using the replication method. Based on the two-tailed t-test, bulk density was statistically uniform for 12 sample locations across the soil surface and throughout the soil profile. The new method proved efficient and effective at producing soil surfaces with identical rough surface microtopography and uniform bulk density.

Fracture and Damage Mechanism of RC Pile Group Foundation under Low Reversed Cyclic Loading

This document explains and demonstrates experimental activity on 4 scale-models of elevated pile cap foundation belonging to a long span continuous bridge. The foundation was composed of 9 piles, pile cap and pier and the special soil box was built to consider soil-pile-superstructure interaction. According to the test result, the development rule of the failure mode, the failure form, the load-displacement hysteretic loops and the plastic hinges mechanism etc. for specimens were summarized. Moreover, the energy dissipation capacity and the viscous damping ratio were gained. The test also provided the data to quantitatively assessment the positive effect of steel protective pipe for RC pile. Fiber beam-column finite element model considering the modified Park-Ang damage index was built in OpenSees. This damage model was proposed to consider the loading path, the pronounced pinching effect of concrete and bond-slip of the reinforcing bars in the paper. In calculation strength degradation and stiffness degradation effects were both embodied. The skeleton curves of test and numerical analysis are both consistent by comparing.

Laboratory Simulation of Urban Runoff and Estimation of Runoff Hydrographs with Experimental Curve Numbers Implemented in USEPA SWMM

The prognostic capabilities of a lumped hydrologic modeling approach may be complicated by routing and connectivity among infiltrative and impervious surfaces. We used artificial rainfall to generate runoff from impervious and bare soil boxes arranged in series to simulate different extents and connectivity of impervious surfaces under different moisture conditions for pervious areas. Curve numbers were calculated from observed rainfall and runoff data, compared with published values, and used in the curve number infiltration algorithm in the U.S. EPA Storm Water Management Model 5 (USEPA SWMM5) to generate runoff hydrographs. Experimental curve numbers were higher than tabular USDA values, ranging from 91 to 96. Simulations of infiltration and runoff response with experimental curve numbers showed overall good agreement with observed data, although SWMM5 was unable to re-create early term infiltration patterns, and simulated runoff lagged observed, which is attributed to implicit accounting for soil moisture and other assumptions of the SWMM5 curve number application. Our results highlight some prospects for the use of curve numbers in modeling infiltration and runoff.

Mechanical Behavior of Anisotropic Sand Ground Beneath Structures Subjected to Cyclic Loading Such as Wave Loading

An experimental study on the mechanical response of anisotropic seabed to wave force and oscillation of man-made structures such as wave dissipating blocks and breakwaters was performed on a model soil box with two-dimensional plane strain condition. Using model ground comprised of Toyoura sand reconstituted by air-pluviation method, a series of cyclic loading tests on model structures under several foundation conditions was conducted at a loading pattern which is capable of simulating the various stress states induced by both oscillation of structure and wave force. Test results showed that the strength and deformation characteristics of model sand deposits are basically identical to those estimated from the conventional cyclic undrained triaxial test and are different depending strongly on the changes in the depositional condition of the ground. Based on the results of model testing, the applicability of countermeasures constructed by both side wall and sheet pile was investigated to prevent ground failure. Considering the model testing results, it was also found that the installation of side walls beneath structures and sheet piles into the ground are advantageous as countermeasures against progressive failure on sand ground subjected to wave loading.

Using Rare Earth Elements to Control Phosphorus and Track Manure in Runoff

Concern over the enrichment of agricultural runoff with phosphorus (P) from land applied livestock manures has prompted the development of manure amendments that minimize P solubility. In this study, we amended poultry, dairy, and swine manures with two rare earth chlorides, lanthanum chloride (LaCl(3).7H(2)O) and ytterbium chloride (YbCl(3).6H(2)O), to evaluate their effects on P solubility in the manure following incubation in the laboratory as well as on the fate of P and rare earth elements (REEs) when manures were surface-applied to packed soil boxes and subjected to simulated rainfall. In terms of manure P solubility, La:water-extractable P (WEP) ratios close to 1:1 resulted in maximum WEP reduction of 95% in dairy manure and 98% in dry poultry litter. Results from the runoff study showed that REE applications to dry manures such as poultry litter were less effective in reducing dissolved reactive phosphorus (DRP) in runoff than in liquid manures and slurries, which was likely due to mixing limitations. The most effective reductions of DRP in runoff by REEs were observed in the alkaline pH soil, although reductions of DRP in runoff from the acidic soil were still >50%. Particulate REEs were strongly associated with particulate P in runoff, suggesting a potentially useful role in tracking the fate of P and other manure constituents from manure-amended soils. Finally, REEs that remained in soil following runoff had a tendency to precipitate WEP, especially in soils receiving manure amendments. The findings have valuable applications in water quality protection and the evaluation of P site assessment indices.

Erosion Control on Roadside Embankment Using Compost

This study explored the potential of using a patent-pending compost as a rainfall and wind erosion control blanket on roadside embankments. A rainfall simulator was constructed to simulate natural rainfall. A soil box was designed and built to accommodate the erosion tests. A sandy loam soil was used as the embankment base soil, and the compost of four different pellet sizes made primarily from cattle manure was applied on the base soil as a surface erosion control blanket. Two compost combinations were tested: (1) filtered compost - composts of three different pellet sizes were laid on the upper one-third, the mid one-third, and the lower one-third sections of the slope, respectively, with finer compost on the upper slope and coarser compost on the lower section of the slope; (2) mixed compost - compost of different particle sizes were mixed together and applied on the base soil. Both configurations were tested under repeated rainfall to evaluate the long-term erodibility. Grasses were seeded in the two combinations to study the germination in the compost and the rainfall erosion resistance of vegetated compost. Experimental results showed that the compost cover in the above configurations significantly reduced soil loss, and the soil loss of the mixed compost with vegetation was within the tolerable limit (5 tons/acre/yr) specified by the U.S. Natural Resources Conservation Service. The runoff was analyzed for its physical and chemical constituents in order to evaluate the environmental impact of the compost application. Wind erosion tests on both the base soil and compost were conducted in a wind tunnel at a U.S. Department of Agriculture facility. A method to estimate the erodibility factor of compost was proposed. This preliminary study showed the potential of this proprietary compost as an effective erosion control material.

Effect of Saturated Near Surface on Nitrate and Ammonia Nitrogen Losses in Surface Runoff at the Loess Soil Hillslope

Water pollution from agricultural fields is a global problem and cause of eutrophication of surface waters. A laboratory study was designed to evaluate the effects of near-surface hydraulic gradients on NO3–N and NH4–N losses in surface runoff from soil boxes at 27% slope undersimulated rainfall of a loess soil hillslope. Experimental treatments included two near-surface hydraulic gradients (free drainage, FD; saturation, SA), three fertilizer application rates (control, no fertilizer input; low, 120 kg N ha-1; high, 240 kg N ha-1), and simulated rainfall of 100 mm h-1was applied for 70 min. The results showed that saturated near-surface soil moisture had dramatic effects on NO3–N and NH4–N losses and water quality. Under the low fertilizer treatment, average NO3–N concentrations in runoff water of SA averaged 2.2 times greater than that of FD, 1.6 times greater for NH4–N. Under the high fertilizer treatment, NO3–N concentrations in runoff water from SA averaged 5.7 times greater than that of FD, 4.3 times greater for NH4–N. Nitrogen loss formed with NO3–N is dominant during the event, but not NH4–N. Under the SA condition, the total loss of NO3–N from low fertilizer treatment was 34.2 to 42.3% of applied nitrogen, while under the FD treatment that was 3.9 to 6.9%. However, the total loss of NH4–N was less than 1% of applied nitrogen. These results showed that saturated condition could make significant contribution to water quality problems.