Erosion Stability Research Articles

Macroscopic Assembly of Materials with Engineered Bacterial Spores via Coiled-Coil Interaction.

Herein, we report macroscopic materials formed by the assembly of engineered bacterial spores. Spores were engineered by using a T7-driven expression system to display a high density of pH-responsive self-associating proteins on their surface. The engineered surface protein on the spore surface enabled pH-dependent binding at the protein level and enabled the assembly of granular materials. Mechanical properties remained largely constant with changing pH, but erosion stability was pH-dependent in a manner consistent with the pH-dependent interaction between the engineered surface proteins. Our finding utilizes synthetic biology for the design of macroscopic materials and illuminates the impact of coiled-coil interaction across various length scales.

Transverse vibration analysis and active disturbance rejection decoupling control of rain erosion whirling arm

The transverse vibration caused by the mass eccentricity of the whirling arm and the unbalanced magnetic pull of the motor rotor is a critical factor that affects the stability and safety of the rain erosion whirling arm. To investigate the transverse vibration characteristics of the rain erosion whirling arm during operation, a four-degree-of-freedom transverse vibration model of the rotor-rain erosion whirling arm is established using the lumped mass method. The differential equation of motion of the rotor-rain erosion whirling arm, considering the influence of mass eccentricity and unbalanced magnetic pull, is then established based on the Lagrange equation. This equation is numerically solved using the Runge-Kutta algorithm to investigate the axis trajectory and amplitude distribution of the rotor-rain erosion whirling arm. To reduce the fatigue damage caused by vibration, the active disturbance rejection decoupling control method is employed. Furthermore, the parameters of the extended state observer are adjusted using pole assignment and bandwidth. The simulation results reveal that the vibration amplitude of the rotating blade can be reduced to within 0.2 mm, referring to the BSS7393 test standard. Additionally, experimental research is conducted to compare the vibration of the rain erosion whirling arm before and after implementing the active disturbance rejection decoupling control. The results demonstrate that the active disturbance rejection decoupling control method effectively suppresses the vibration of the rain erosion whirling arm, illustrating its feasibility and effectiveness for system vibration control.

Spatial-temporal variation and correlation between vegetation coverage and soil conservation of Ten Kongdui watershed in the Yellow River basin

The Ten Kongdui watershed is an essential part of the upper Yellow River baisn of China. The ecosystem in this region has low stability and hazards of sandstorm and soil erosion are serious. By studying the spatio-temporal changes and spatial correlation between vegetation cover and soil conservation, the inhibition effect of vegetation on soil erosion in time and space can be clarified, and the driving factors of soil erosion in a certain area can be further explained. The research results provide data support for artificial vegetation construction and soil erosion control in the Yellow River basin in the future. In this study, the invest model was used to calculate the soil retention of the watershed, and then the spatial autocorrelation analysis was used to analyze the vegetation coverage and soil retention in space. The relationship between changes of the vegetation coverage and soil conservation during 2000–2020 in the Ten Kongdui watershed is analyzed in this paper. The research shows that: (1) During the research period, the vegetation coverage maintained an increasing trend in Ten Kongdui watershed; (2) From 2000 to 2020, with the increased vegetation coverage, soil retention increased, indicating that increasing vegetation coverage can effectively prevent soil erosion; and (3) Vegetation coverage and soil conservation presented a local spatial auto-correlation, Moran’s I index was less than 0, but the years from 2000 to 2020 witnessed gradual growth of the correlation coefficient. There are significant differences in spatial distribution. ‘High-high’ and ‘low-low’ are sporadically distributed in the sandstorm area on the middle reaches of Kubuqi and sporadically in the hilly and gully areas on the upper reaches. Moreover, ‘high-low’ and ‘low-high’ correlation coefficients were distributed in gully areas on the upper reaches and alluvial plains on the lower reaches. The alluvial plains on the lower reaches are mainly farmland ecosystems, with a high NDVI in the growing season but poor soil erosion resistance and weak soil conservation ability. The results emphasized the importance of vegetation coverage change in space for soil conservation of different type of underlying surfaces. The vegetation coverage change effects of soil conservation in plain terrain will be muted. This work provided a certain theory and criterion for us to further research the predictive model of soil erosion .

Study of experimental and numerical simulation on the influence of gravel on the interflow of slope land.

The formation of interflow is of great significance for the stability of mountain slopes and soil erosion. Hillsides are often covered with a certain amount of gravel, and research on interflow of slope land with different gravel ratios needs to be carried out. This article is based on indoor experiments and numerical models to study the formation law of interflow in hillside soil under different gravel coverage ratios. It was found that the interflow in the soil rapidly increased in the early stage and began to decrease after briefly reaching equilibrium. The formation of interflow is a complex process that is related to slope, soil characteristics, and rainfall intensity, but the correlation is not high when viewed separately. The lattice Boltzmann model can effectively simulate such problems and achieve high simulation accuracy. The [Formula: see text] of the simulated data and measured data ranged from 0.5217 to 0.7403, and [Formula: see text] of the simulated data and measured data ranged from 0.4051 to 0.5711.

Similarity Model Test on Rainfall Scouring Mechanism of High-Speed Railway Subgrade Slope

The subgrade slope, when exposed to the natural environment for a long time, is easily affected by rainfall scouring, which leads to a large loss of filling materials and soil sliding, affecting the stability of the subgrade slope. In this paper, the model test of a high-speed railway subgrade slope under rainfall scouring was conducted to quantitatively study the occurrence and development process of subgrade slope erosion. Compared with the model test results and the theoretical results, the incipient flow velocity formula of coarse-grained soil was verified. Then, the curve of rainfall intensity varied with the incipient particle size under different rainfall intensities, slope gradients and soil particle grading conditions was analyzed. Results show that during rainfall scouring, the smaller the particle size, the earlier the scouring erosion occurs. In addition, the soil particles on the slope bottom were scoured more severely than those on the slope upper. With the increase in rainfall intensity, slope gradient, and the change in soil particle gradation (removing the minimum particle size), the incipient flow velocity of soil particles on the slope will be reduced. The curve of the rainfall intensity varied with the incipient particle size, which plays an early warning role in the analysis of slope erosion stability and reflects the particle size range of the scouring erosion incipient on the slope surface under different rainfall intensities, providing the basis for the analysis of slope erosion stability and the slope protection design of the high-speed railway subgrade slope.

Experimental Study on Pore Pressure Variation and Erosion Stability of Sandy Slope Model under Microbially Induced Carbonate Precipitation

With the development of a free trade port on Hainan Island, the construction of tourist roads around the island is currently underway. However, the weather conditions on Hainan Island, which include strong typhoons and rainstorms, pose challenges for the construction of highway-cutting slopes on the coastal weak sandy terraces. These slopes are susceptible to sand loss and erosion from rainfall. To address this issue, MICP green spray irrigation solidification technology is used to strengthen the sandy cutting, and pore water pressure monitoring is carried out on the slope model during MICP solidification and rainfall scour. Combined with the model pore water pressure and flow slip failure pattern, a dynamic analysis was conducted. The results show that MICP sprinkler irrigation technology can solidify the surface of the slope model in a short time, and after three sets of rotation reinforcement, the model achieved a cementation depth of 4 cm, with a well-reinforced surface and closely connected sand samples. Under the erosion effect of simulated rainfall intensity, the sand loss of the slope was weakened, without damage to the sand binding, and the integrity was enhanced. The cementation between the sand grains facilitated the conversion of most of the rainfall into runoff. However, despite these efforts, the slope eventually slid after 150 s. During the sliding process, the leading edge of the slope model lost sand and became unloaded, and the failure mode was graded a creep slip failure. Finally, the slope was divided into several blocks due to the continuous expansion of cracks following the slope failure. The erosion stability of the sandy slope under heavy rains was optimized and the sand loss was prevented effectively. This study proposes a new method of MICP remediation techniques that serve as a new test basis for the practical application of MICP technology in engineering projects.

A potential sustainable technique to entrap contaminants against rill erosion based on MICP

Health risks due to toxic metals (TM) contamination is a global concern. Toxic metals could be release to the environment due to soil erosion. The present study was aimed to prove the synergistic mechanisms of microbially induced calcium carbonate precipitation (MICP) on improving the strength properties of soil particles toward rill erosion, as well as immobilizing toxic metals into stable crystals. Hence, laboratory batch studies were conducted to evaluate the rill erosion stability as well as Cd, Pb and Zn removal ability based on bioprecipitation through MICP, using urease producing bacteria. Results revealed that the application of the strain Bacillus pasteurii PTCC1645 in MICP process of test model treated with 500 mM cementation solution showed a great potential to decrease sand lost to below 20% with the flow rate of 15 ml/min with highest strength (131 KPa) and the highest calcium carbonate content (0.84%). Moreover, the immobilization of the toxic metals in biotreated test models above 50 mM under the flow rate of 3 ml/min showed the efficiency of Pb, Zn and Cd ions by 100%. SEM proved the presence of calcite among the sand particles which could be attributed to the effectiveness of the strain. Energy-dispersive X-ray spectroscopy(EDS) analysis revealed the presence of toxic metals, while were transformed into carbonates by MICP of PTCC1645. Hence, toxic metals have stronger stability encountered with rill erosion and low toxicity compared with metal ions. The present study illustrated that the carbonate-biomineralization can offer an effective and eco-friendly approach to immobilize soluble toxic metals and that MICP may play an important role in metal bioconservation during rill erosion.

Internal Erosion Stabilization of Cohesionless Soil Using Lime

Soil embankments are valuable for the adequate reserve and supply of water to multiple industries. However, they are susceptible to internal soil erosion, which may ultimately lead to structural collapse. To counteract this issue, soil stabilization is practiced in the construction industry. This paper proposes the internal erosion stabilization of cohesionless soil using quicklime. For this research, two cohesionless soil types were investigated and treated with quicklime: poorly graded and well-graded cohesionless soils. For poorly graded soil, the lime percentage varied from 0.0% to 6.0% based on the soil’s weight, while for well-graded soil, it ranged from 0.0% to 3.0%. All the soil specimens were cured for 24 h and tested using the hole erosion test (HET) to replicate the internal erosion effortlessly. The analyzed results demonstrated the efficiency of quicklime as an internal erosion stabilizer for cohesionless soils. The optimum lime content for poorly graded cohesionless soils was 5.0%; for well-graded, the percentage was approximately 3.0%. Moreover, adding lime significantly improved the strength, critical shear stress, and erosion rate index of the soil.

Tailings dams: Assessing the long-term erosional stability of valley fill designs

Tailings is a generic term for waste material from the extraction and processing of minerals and frequently contain mineral and chemical residues. They are usually highly erodible and transportable via fluvial processes. Tailings are commonly stored in ‘tailings dams’ and such dams are a feature of many mine sites. As they impound water and sediment, tailings dams can be at risk from both catastrophic and gradual failure, especially if unmanaged. A fundamental question for their management is, can tailings dams ever be walk-away structures? Catastrophic failure occurs when there is a large scale rapid structural failure of the dam wall suddenly releasing large volumes of water and sediment. However, over time, there will the increased risk of gradual failure by the slow infilling of the dam and the erosion of the dam wall. Failure can occur where water overtops the dam wall and then incises through the wall due to a loss of freeboard in the dam, a situation which is more likely in legacy tailings dams where they have been filled, vegetated and abandoned. Here, firstly, a computer based landscape evolution model (CAESAR-Lisflood) is employed to assess a hypothetical tailings dam failure by erosion. Secondly, using an idealised example, it is demonstrated that given average climate conditions a dam can be sufficiently robust to last centuries. Thirdly, and longer term it is demonstrated that the tailings can be contained if (a) maintenance is conducted to increase the dam wall height over time or (b) a more robust dam wall is constructed to manage extreme events. However, erosion and infill will continue to reduce the integrity of any structure over time. Therefore, it is highly likely that tailings dams will require continued monitoring and maintenance. The method outlined provides a new tool for assessing any tailings facility for its erosional stability.

Anthropogenic pressures induced hydromorphodynamic changes of riverine islands in the Upper Jingjiang reach along the Changjiang (Yangtze) River

Riverine islands are widespread fluvial landforms with exceptional economic and environmental values. However, anthropogenic pressures have further induced drastic changes worldwide in fluvial islands, which endanger fluvial organism habitation and enable potential ecological degradation. Here, the hydromorphodynamics on these prominent riverine landforms of the seriously regulated Upper Jinjiang reach (UJR) of the Changjiang (Yangtze) River were detected based on the Google Earth Engine (GEE) platform between 1988 and 2019. The results indicated that total vegetated islands area in the UJR experienced expansion, while bars area exhibited a dramatic decrease by 15% between 1988 and 2019. Given the total areas and their subaquatic bars' volume variations, the island's evolution could be divided into “deposition–erosion–stabilization” stages. During the deposition phase from 1988 to 1999, the bars volumes showed a gradually increasing trend, and then it shifted to erosion between 1999 and 2010. After 2010, the islands maintained stability with a total volume of approximately 177 × 106 m3. The multi-year sediment and water discharge variations contributed to the evolution of riverine islands. In particular, resulting from the Three Gorges Dam (TGD) project in 2003, the fluvial sediment load and duration of overbank discharges (25000 m3/s) decreased significantly, which were the dominant factors inducing islands with their subaquatic bars shrinkage. Recent multiple island protection projects were responsible for defending islands with their subaquatic bars against erosion and maintaining their stability. This work reveals the islands' evolution in the UJR response to the TGD effect and local artificial engineering, which is vital for managing riverine islands in global rivers affected by nature and human activities.

Chemical initiator-free synthesis of Poly (acrylic acid-co-itaconic acid) using radiation-induced polymerization for application in dental cements

Glass ionomer cements (GICs) have been explored by the researchers around the world for their applications in dentistry because of numerous advantages such as their distinctive clinical properties e.g., anticariogenic properties, chemical adhesion to tooth surface and biocompatibility. However, the GICs prepared through the conventional chemical polymerization methods suffer from many disadvantages including release of unreacted monomer and toxic initiator into oral cavity. Therefore, in the present work, attempts were made to synthesize the polymer to be used in GICs using toxic initiator-free γ-irradiation technique. Different molar ratios of acrylic acid and itaconic acid were polymerized using Co-60 γ-source to produce Poly(acrylic acid-co-itaconic acid, PAA-co-IA). The synthesized copolymers, were characterized by FTIR, DSC and TGA. Compressive strengths of GIC specimens formed by incorporating fluoro-aluminosilicate (FAS) glass with synthesized copolymers, were investigated after storing for 1, 7, 14 and 28 days in distilled water. FESEM was performed to study the surface morphology of the cements. The working and setting time were determined as per ISO4049. The copolymers PAA-co-IA were synthesized via γ-irradiation method to form GIC. The results show that DC/PAA-co-IA/2:1 have higher Compressive Strength (CS) of 157.65 ± 4.02 M Pa as compared to control. High acidic erosion stability was observed, which was in agreement with the FESEM studies showing lower cracks and voids. Thus, γ-irradiation polymerization technique was initiator-free, facile and proficient for the synthesis of copolymers used in preparing GICs.

Gravel Mining Activity Impact on Riverbed Erosion and Bridge Foundation Stability

Geomorphological processes pose a risk that deserves attention and planning to avoid that, especially in the section near to east of Tuz bridge. This section of the valley facing a dramatic increase in gravel excavation and sorting of aggregates, consequence led to a change in the pattern of river branches flow from an anabranching river to a single-channel river, which led to a concentration of river discharge during floods. On 9th December 2018, Tuz Bridge was failed due to a heavy rainstorm three days preceding the failure event. The current study aims to conduct a field survey of all the human activities in the study area to assess river changes from remote sensing data the amount of runoff and river peak discharge based on rainfall data using SCS-CN method. In this study, ArcGIS, ArcGIS Earth, Google Earth, and WMS software are incorporated in the data analysis. The revealed results indicate the severe modification of valley morphology and converting the river pattern to flow during flood within a single channel with flow speed exceeded the critical velocity to induce vertical erosion of gravel and sands under the foundations of the bridge and causing the displacement and settlement of the bridge. The study recommends the local administration prevent gravel mining from the river valley at the upstream area of the bridge

Evaluating a new landform evolution model: A case study using a proposed mine rehabilitation landform

AbstractLandform evolution models are powerful tools for determining long‐term erosional stability and denudation rates spanning geological timescales. SIBERIA, CAESAR and CHILD are examples of these model. The newly developed State Space Soil Production and Assessment Model (SSSPAM) coupled soilscape‐landform evolution model has the ability to assess overall erosion rates of catchment scale landforms either using short‐term precipitation events, variable precipitation or time‐averaged precipitation (annual average). In addition, SSSPAM has the capability of developing the subsurface soil profile through weathering and armouring. In SSSPAM, physical processes of pedogenesis such as erosion and armouring, diffusion, sediment deposition and weathering are modelled using a state space matrix approach. In this article we simulate the short‐term evolution (100 years) of a proposed post‐mining landform using both SIBERIA and SSSPAM and compare the erosion and sediment output results. For the short‐term simulations SSSPAM's armouring capability was disabled. The models were then used to simulate the evolution of the catchment for 10,000 years. Results demonstrate that the short‐term SSSPAM simulation results compare well with the results from the established landform evolution model SIBERIA. The long‐term armouring disabled SSSPAM simulations produces simulated erosion rates comparable with SIBERIA simulations both of which are similar to upper limit of field measured denudation rates. The SSSPAM simulation using armouring demonstrated that armouring reduced the erosion rate of the catchment by a factor of 4 which is comparable with the lower limit of field measured denudation rates. This observation emphasizes the importance of armouring in long‐term evolution of landforms. Soil profile cross‐sections developed from the same results show that SSSPAM can also reproduce subsurface soil evolution and stratification and spatial variability of soil profile characteristics typically observed in the field.

Soil attributes as indicators of the stabilization process of erosion in gullies at different formation stages in the southeast region of Brazil

Water erosion is one of the main forms of soil degradation, causing economic, environmental, and social damage. This study evaluated the effects of different formation stages of gullies (initial - IG; juvenile- JG; mature - MG; and senile - SG) on the chemical, organic carbon and microbiological attributes of soil, using a secondary forest (SF) and two areas of pasture as references in the “Mar de Morros” environment of the Brazilian Atlantic Forest biome. Soil samples (depth 0–0.05 m) were collected at the end of the rainy and dry seasons. Gullies in different stages of formation promote a decrease in soil fertility and modification of microbiological attributes, particularly when compared with secondary forest areas. Reductions of over 60% in total organic carbon (TOC), oxidizable organic carbon (POXC), FDA activity, β-glycosidase, acid phosphatase, C and N from microbial biomass, basal soil respiration (BSR) and glomalin-related soil protein (GRSP) were observed in gullies in early (IG) and intermediate (JG and MG) stages when compared to SF. It was found that the effect of erosion on soil chemical and microbiological attributes is more intense in gullies in the initial and intermediate stages compared with those in the senile stage (SG). Using multivariate PCA, the microbiological and chemical attributes of the soil are discriminated between gullies with distinct formation stages. Chemical attributes, TOC, POXC, FDA activity, β-glycosidase, acid phosphatase, MBC and MBN, BSR, and GRSP are good indicators for evaluating the process of erosion stabilization in gullies.

Interaction of biopolymer with dispersive geomaterial and its characterization: An eco-friendly approach for erosion control

Addition of natural polymer or biopolymer is considered as a novel, cost-effective and eco-friendly soil modification approach mainly pertaining to erosion stability. The present study focuses on the interaction of three types of biopolymer i.e., xanthan gum, guar gum and carboxymethyl cellulose to stabilize two dispersive industrial waste materials i.e., fly ash and coal mine overburden soil. The results found that all the three biopolymers enhanced the index and geotechnical properties of fly ash and mine overburden due to their high viscosity, aggregation, adsorption and cross-linking bond formation. However, the rate of enhancement varies with the type and concentration of biopolymer. The biomodified soil were evaluated for erosion stability against wind and water by performing pinhole test, cylindrical dispersion, surface resistance and water retention test. It concluded that a very minimal fraction, 1% of biopolymer solution could mitigate the dispersiveness of the geomaterial. Additionally, the results of microscopic analysis by scanning electron microscope assist to correlate the morphological changes with the engineering properties of biomodified soil due to the interaction of soil with the long-chained biopolymers strings. Finally, leachate and cost analysis of the biopolymer modified material was assessed to evaluate the efficiency of the biomodification.

A GIS-Based Spatial Analysis Model Approach for Identification of Optimal Hydrotechnical Solutions for Gully Erosion Stabilization. Case Study

The accentuated degradation of agricultural lands as a result of deep erosion processes is the main problem identified in abandoned agricultural lands under the rainfall intensities, increasing number of hot days, indirectly under the impact processes derived from them (soil erosion, vegetation drying, etc.), as well as inadequate or poor management policies implemented by local authorities. The present study aims to develop and present a methodology based on GIS spatial analysis to choose the best hydro-amelioration solution for the arrangement of a complex ravine that negatively affects the entire agroecological area in its immediate vicinity. The proposed model is developed on spatial databases obtained based on UAV flights, the simulation of flow rate values and the establishment of three hydraulic analysis models through the HEC-RAS software with the main purpose of evaluating the results and databases, in order to identify the best implementing model for the stabilization and reduction in erosion within the analysed area. The comparative analysis of the three analysed scenarios highlighted the fact that a dam-type structure with overflow represents the best hydro-ameliorative solution to be implemented in the present study. The accuracy of the obtained results highlights the usefulness of developing GIS models of transdisciplinary spatial analysis to identify optimal solutions that can be implemented in territories with similar characteristics.

Grouting below Subterranean Water: Erosional Stability Test.

The article is focused on the medium-term negative effect of groundwater on the underground grout elements. This is the physical–mechanical effect of groundwater, which is known as erosion. We conduct a laboratory verification of the erosional resistance of grout mixtures. A new test apparatus was designed and developed, since there is no standardized method for testing at present. An erosion stability test of grout mixtures and the technical solutions of the apparatus for the test’s implementation are described. This apparatus was subsequently used for the experimental evaluation of the erosional stability of silicate grout mixtures. Grout mixtures with activated and non-activated bentonite are tested. The stabilizing effect of cellulose relative to erosion stability has been also investigated. The specimens of grout mixtures are exposed to flowing water stress for a certain period of time. The erosional stabilities of the grout mixtures are assessed on the basis of weight loss (WL) as a percentage of initial specimen weight. The lower the grout mixture weight loss, the higher its erosional stability and vice versa.

Rigidity of “Warsaw clay” from the Poznań Formation determined byin situtests

AbstractThe character of morphogenetic processes occurring within river valleys depends on the mechanical and hydrogeological properties of deposits that build up such landforms. In the case of the Polish Lowlands, a series of Pliocene clay lake sediments (so-called Poznań mottled clays) plays a special role. Their current locations and properties are associated with specific sedimentation conditions and glacitectonic deformations, which the soils have been subjected to many times in Pleistocene. Their presence in the lithological profile influences dynamics of slope processes in valleys’ escarpment zones and channel erosion stabilization. In this article, the “Warsaw clay” from the Poznań Series Formation is presented in comparison with other cohesive Quaternary sediments, which are mostly building neighboring outcrops. This article analyzes the Seismic Dilatometer (SDMT) results and a method of interpretation to determineIR, plasticity index, and liquid limit (LL) parameters. The undrained shear strengthSuwas determined based on the Cone Penetration Test (CPT), SDMT, and laboratory test results. Spatial variability of the strength and deformation parameters in the study area were determined using dilatometer test (SDMT) results. Finally, the nomogram chart is proposed to obtain the rigidity index (IR) of the preconsolidated Pliocene clays, depending on bothp0andp1pressures from SDMT and effective vertical stressσv0′{\sigma }_{\text{v0}}^{^{\prime} }and pore water pressureu0.

Mining rehabilitation – Using geomorphology to engineer ecologically sustainable landscapes for highly disturbed lands

Mining is essential to the human economy and has been conducted for millennia. In the past ~60years, the scale of disturbance created by mining has grown larger in response to economic demands and technology capacity. However the scale of disturbance from mining is dwarfed by that of urban expansion and agriculture. Nevertheless, it is well recognised that mine sites have radically disturbed abiotic and biotic system components that, post-mining need to restore new land uses and ecosystem goods and services. In many cases, such aims demand a geomorphic integration with the surrounding undisturbed landscape. Erosional stability based on geomorphic principles is the first and most important part of the process. Without erosional stability, vegetation will be difficult to establish and maintain and soil and nutrients will be lost from the site. In this review we outline this process and methods by which a geomorphic and integrative landscape can be established. We also examine the issue of establishing a self-sustaining landscape that is similar to that of the prior undisturbed landscape. Here we argue that this is not possible in almost all situations, however the development of a new and ecologically successful, albeit different landscape is. The community needs to accept that mining, like agriculture, is essential to the modern economy and that a past landscape cannot be replaced with the same, but a new, functional and productive one can be developed. However, the ability to do this and ensure long-term ecological sustainability is questionable for many sites and considerable effort needs to be made to develop the technology to ensure that this will occur. We outline a way forward, based on geomorphic design and modelling.

Site Characterization of Soil-rock Mixture Sedimentary Stratum Based on HVSR Analysis in the Chinese Loess Plateau

The soil-rock mixture sedimentary stratum is a compound with complex and loose topography, of which the structure is difficult to detect by the ordinary geophysical method. There is a need for a convenient, efficient and effective geophysical method to detect site effects in this area. This paper is an application of the S wave velocity profile inversion for the soil-rock mixture sedimentary stratum, using HVSR (Horizontal to Vertical Spectral Ratio) analysis of ambient noise by some three-component observations in the Chinese Loess Plateau. We carried out the measurement using three nested circular arrays and data recording systems with a spectrum expansion circuit. Inversion of the HVSR curves was performed by a three-layer model. Results of geological observation reveal that the upper part of the sedimentary stratum is Quaternary strata containing a large amount of humus and loess, the middle layer part is the stratum of the loose gravel and the under part is completely weathered granite with homogeneous lithology and fewer rocks. Interpretation results are consistent with previous drilling data, providing a valid geophysical basis for evaluating the stability of the soil erosion and designing a reasonable water and soil erosion control scheme.