Type Of Backfill Research Articles

Morrey Award 2023: radial head donor plug for capitellum osteochondral autograft transfer: a cadaveric biomechanical analysis

BackgroundLimitations to using the knee as donor cartilage include cartilage thickness mismatch and donor site morbidity. Utilizing the radial head as donor autograft for capitellar lesions may allow for local graft harvest without distant donor site morbidity. The purpose of this study is to demonstrate the feasibility of performing local osteochondral autograft transfer from the non-articular cartilaginous rim of the radial head to the capitellum. Additionally, we sought to determine the load to failure of the radial head after harvest. MethodsSixteen matched cadaveric elbows were utilized. A Kaplan approach was performed in half of the specimens and an extensor digitorum communis (EDC) split in the other half. 6mm and 8mm capitellar cartilage defects were created. A donor plug was harvested from the rim of the radial head and transferred to the capitellum. In half of the specimens, the donor site was backfilled with autograft from the recipient plug. The other half were backfilled with calcium-phosphate cement. The radial head was removed from the specimen and biomechanical analysis performed. ResultsBoth surgical approaches had adequate exposure to access the lateral 2/3 capitellar lesions in all specimens. The medial third of the capitellum was less accessible in EDC split approaches (1/8) compared to the Kaplan approach (6/8 p = 0.01). The average cartilage thickness of the peripheral rim of the radial head and capitellum was 2.5mm (range 1.8-3.2, SD 0.4) and 2.2mm (range 1.8-3, SD 0.3), respectively. During the procedure, 2 of 8 radial heads fractured in the 8mm plug group. No radial heads fractured in the 6mm group (p = 0.47). Biomechanical testing demonstrated a mean load to failure of 1993N with no difference between groups when stratified by donor plug size or type of backfill. ConclusionThis study demonstrates that the non-articulating peripheral cartilaginous rim of the radial head could be a local harvest site for osteochondral autograft transfer for capitellar lesions up to 8mm in diameter. The cartilage thickness of the radial head closely approximates the capitellum. Biomechanical analysis did not demonstrate a significant difference in load to fracture when backfilling the radial head harvest site with autograft bone or calcium phosphate cement. After harvest, the radial head could withstand forces much greater than those seen across the elbow when non-weight bearing. Further investigation is needed to determine how to mitigate the risk of iatrogenic fracture with this operation.

Method of Average Vertical Earth Pressure for HFCCTs Based on Differential Settlement

AbstractThis paper presents a modified and simplified calculation method, taking into account the differential settlement between the soil columns surrounding the cut-and-cover. High-filled cut-and-cover tunnels (HFCCT) are usually subjected to high earth pressures above the top of the CCT due to an ultra-high backfill. However, the estimation methods for earth pressure above the top of CCT are ambiguous. Through the theoretical analysis of the average vertical earth pressure (AEP) at the top of the CCT, it is found that an additional earth pressure above the top of the overburden pressure is induced, and the magnitude is related to the differential settlement between interior and exterior soil columns. Thus, through a combined theoretical derivation and numerical analysis, a modified formula is proposed. The results show that the vertical earth pressure increment above the top of CCT can be linearly correlated to the differential settlement. In addition, the correlation needs to be calibrated by considering several effects on sites, such as slope angle, groove-width ratios, cross-sectional shape, and the type of backfill. The change in influencing factors has no effect on the function type of the p−δ fitting curve, but it will affect the coefficient k.

Wonorejo dam operation and storage analysis against climate change

Climate change affecting rain intensity within catchment and increase the potential hydrometeorology disasters. Wonorejo Reservoir as a multipurpose dam requires an operational plan and water allocation to fulfill downstream needs, such as irrigation, hydropower, microhydropower, domestic industry uses and flood control. Wonorejo Dam is a backfill type dam with High Water Level (HWL) elevation is +183.00 mSHVP and Low Water Level (LWL) elevation is +141.00 mSHVP, Total storage capacity Wonorejo Reservoir is 109.118 million m3 (2021) or 89.4% from initial total storage capacity (2000), in 2050 predicted sediment volume increase to 17.73 million m3 or 17.6% reservoir capacity and 2050 capacity volume is 100,585 million m3 or 82.4% from initial total storage capacity. Annual Reservoir Operation Plan and Annual Water Allocation Plan for Wonorejo Reservoir in 2022/2023 as water services December 2022 to November 2023 periode, Wonorejo Reservoir elevation at the end of May 2023 reaches HWL and lowest water elevation is +162.64 mSHVP in the first week of November 2023.

Closure to “Physical Modeling of Temperature Influence on Performance of Geogrid-Reinforced Retaining Walls Considering Backfill Type Effect”

Closure to “Physical Modeling of Temperature Influence on Performance of Geogrid-Reinforced Retaining Walls Considering Backfill Type Effect”

Discussion of “Physical Modeling of Temperature Influence on Performance of Geogrid-Reinforced Retaining Walls Considering Backfill Type Effect”

Discussion of “Physical Modeling of Temperature Influence on Performance of Geogrid-Reinforced Retaining Walls Considering Backfill Type Effect”

Engineering Properties of Novel Vertical Cutoff Wall Backfills Composed of Alkali-Activated Slag, Polymer-Amended Bentonite and Sand.

The workability, hydraulic conductivity, and mechanical properties are essential to contaminant containment performance of cementitious backfills in vertical cutoff walls at contaminated sites. This study aims to investigate the engineering properties of a novel vertical cutoff wall backfill composed of reactive magnesia (MgO)-activated ground granulated blast furnace slag (GGBS), sodium-activated calcium bentonite amended with polyacrylamide cellulose (PAC), and clean sand (referred to as MSBS-PAC). Backfills composed of MgO-activated GGBS, sodium-activated calcium bentonite, and clean sand (referred to as MSBS) were also tested for comparison purposes. A series of tests were conducted which included slump test, flexible-wall hydraulic conductivity test, and unconfined compression test. The pore size distributions of two types of backfills were investigated via the nuclear magnetic resonance (NMR) technique. The results showed the moisture content corresponding to the target slump height was higher for MSBS-PAC backfill than that for MSBS backfill. The MSBS-PAC backfill possessed lower pH, dry density, and higher void ratio at different standard curing times as compared to MSBS backfill. The unconfined compressive strength and strain at failure of the MSBS-PAC backfill were noticeable lower than those of the MSBS backfill. In contrast, the hydraulic conductivity of MSBS-PAC backfill was approximately one order of magnitude lower than that of the MSBS backfill, which was less than 10-9 m/s after 28-day and 90-day curing. Lower hydraulic conductivity of MSBS-PAC backfill was attributed to the improvement of pore structure and pore fluid environment by PAC amendment.

Soil Erosion Due to Defective Pipes: A Hidden Hazard Beneath Our Feet

Sinkholes are a significant underground hazard that threatens infrastructure and lives and sometimes results in fatalities. The annual cost of sinkhole damages exceeds $300 million, although this estimate is likely underestimated due to the need for national tracking. Sinkholes can also alter natural drainage patterns, leading to increased flood risk. While natural sinkholes occur, those in urban areas are predominantly manmade, caused by soil erosion from defective pipes, typically due to aging. Climate change, storm surges, and urbanization have accelerated subsidence in urban environments, posing greater risks to critical infrastructure and densely populated areas. Extensive research has focused on soil erosion in dams; however, this knowledge does not necessarily apply to erosion through orifices, where gravity and other factors play significant roles. This paper presents a critical literature review on internal soil erosion due to defective pipes (SEDP). The review highlights that hydraulic loading, backfill type, and pipe conditions (defect shape, size, and depth) influence SEDP. Key findings from experiments and numerical studies are summarized, while mechanisms and knowledge gaps are identified. However, it is concluded that the current understanding in this field remains limited, underscoring the urgent need for further experimental and numerical research to expand the knowledge base on SEDP.

Analisis Stabilitas Lereng Bendungan Terhadap Beban Gempa sebagai Upaya Pengurangan Bencana (Studi Kasus: Bendungan Jlantah)

Indonesia is a country that has quite high seismic activity and is prone to earthquake hazards, so the construction of embankment dams in Indonesia needs to pay attention to stability against collapse due to soil mass and earthquake loads. Jlantah dam is located in Karanganyar, Central Java. This dam is planned for irrigation needs of 1493 hectares and raw water of 150 liters/second. This study aims to determine the safety factor (Fs) on the Jlantah Dam body. The method used is a quantitative data analysis method, the calculation of the earthquake coefficient corrected by OBE and MDE, carried out with the help of a computer program, namely GeoStudio 2012. Meanwhile, if the earthquake coefficient is known not to be Fs 1.5. The method used is based on references from KP 02-Planning Criteria for Main Building Section and KP 06-Planning Criteria for Parameters Section, and Pd T-14-2004-A. The terms (Fs 1,2) which are used as the theoretical basis are quoted from the theory of Prof. Hoek (1981) stated that by knowing the earthquake coefficient, Fs 1.2 can be used, while if the earthquake coefficient is not known Fs 1.5 Analysis of Earthquake Backfill Type Dam Stability. From the results of the study, it was found that at the time of maximum water and the earthquake for the road dam body was declared from a good structural failure. The results of the bottom study on MDE earthquake conditions from the maximum water level obtained Fk > 1.0 Fk minimum, the maximum water level obtained Fk > 1, 2 Fk minimum with OBE earthquake conditions.

A Numerical Investigation of Induced and Embedded Trench Installations for Large-Diameter Thermoplastic Pipes under High Fill Stresses

The induced trench installation method is applied by placing material with high compressibility on rigid pipes to reduce the earth pressures acting on them. Although the performance of this method for rigid pipes has been investigated, research on thermoplastic pipes is very limited. In this study, induced trench installation (ITI) and embedded trench installation (ETI) of large-diameter thermoplastic pipes subjected to high fill stresses were investigated by numerical analysis. The numerical model has been verified by considering the field experiments, and a series of analyses were carried out by placing Expanded Polystyrene Foam (EPS Geofoam) in ITI and ETI models. Pipe stresses and deflections were evaluated by considering the pipe diameter, stiffness, and backfill properties. The ITI and ETI models in thermoplastic pipes reduced the stresses acting on the pipes and increased the positive arching regardless of the deflection of the pipe. For pipes with an inner diameter of 0.762 to 1.524 m under 30 m of fill stress, approximately 1.5 to 3.0% deflection occurred. In the ETI model, the horizontal earth pressure in the spring line of the pipe decreased from 65 to 40% depending on the backfill type, and an approximately uniform stress distribution was formed around the pipe.

PETROLOGI DAN ESTIMASI SUMBER DAYA BATUAN TANAH URUG PADA PADAWILAYAH EKSPLORASI DI DAERAH TAROKAN, KAB. KEDIRI, JAWA TIMUR

Kediri Regency is a potential area for mining minerals. One of the rock excavation materials found in Kediri Regency is the type of andesite and backfill. Backfill is a mineral as a result of weathering of the parent rock, which is rich in andesite fragments and silica elements. This research was conducted at the exploration location of Tarokan Village, Tarokan District, Kediri Regency. The study was conducted using petrological analysis to obtain rock types and estimates of the availability of these minerals at the research site. Based on the results of petrological analysis, it shows that the sample is a type of backfill and andesite. However, the presence of all samples was dominated by samples of backfill that were present in abundance in as much as 98 % of the total exploration area. Based on the results of the estimation of backfill resources from geological modeling and volumetric calculations from the triangulation concept at an elevation of 110-72 mdpl, the measured resource of the Sandy Tuff unit (TU) has a volume of 2,514,150 m3, based on the results of the analysis of the average rock density of 2.172 g/cm3, the tonnage of the sandy tuff unit is 5,460,734 tons, with the tonnage of backfill from tuff 4,203,659 tons, and andesite tonnage 1,257,075 tons.

Strength and Rheology of Cemented Pastefill Using Waste Pitchstone Fines and Common Pozzolans Compared to Using Portland Cement

Cemented pastefill is one of the most popular backfill types that use waste mill tailings to backfill and stabilise the mined-out voids in underground mines. Cement dosage in the range of 3–7% is added to the tailings to increase the strength of cemented pastefill to serve as wall support when extracting adjacent stopes. Cement is expensive and contributes significantly to the cost of backfilling even with small dosages. Moreover, the production of cement is energy intensive and contributes to the emission of carbon dioxide. Partial replacement of cement with supplementary cementitious materials can significantly reduce cost and make mine backfilling more environmentally friendly. This paper reports the findings from a laboratory test programme on the optimization of mix designs using fly ash, slag, pitchstone fines, and polycarboxylate plasticizer. Results indicated that apart from common pozzolans like fly ash and slag, the pitchstone fines attained comparable unconfined compressive strength when replacing cement by 10–20%. The findings are useful for the mining and civil industries trying to dispose the mine waste or reusing it as backfill or as construction material.

Physical Modeling of Temperature Influence on Performance of Geogrid-Reinforced Retaining Walls Considering Backfill Type Effect

Physical Modeling of Temperature Influence on Performance of Geogrid-Reinforced Retaining Walls Considering Backfill Type Effect

Assessment of membrane and diffusion behavior of soil-bentonite slurry trench wall backfill consisted of sand and Xanthan gum amended bentonite

The diffusion and semi-permeable membrane behavior are significant for evaluating pollution containment effectiveness of soil-bentonite slurry trench wall backfill (referred to as SB backfill) at contaminated sites. In this study, chemico-osmotic tests were performed on xanthan gum amended SB backfill (referred to as XGSB backfill) and conventional SB backfill utilizing zinc nitrate and lead nitrate solutions as tested liquids. The effective diffusion coefficient (D*), retardation factor (Rd), and chemico-osmotic efficiency coefficient (ω) of the backfills were evaluated. The results revealed that each tested backfill behaved as a semi-permeable membrane material with measured ω ranging from 0.015 to 0.14 and 0.007 to 0.05 when exposed to lead and zinc solutions with concentrations varying from 0.5 to 50 mM, respectively. The ω and Rd values for the backfills decreased with increasing concentrations of the tested solutions, while the D* of heavy metal cations increased, regardless of backfill type and tested solution type. Compared to the SB backfill, the ω and Rd of the XGSB backfill were higher while the D* was lower. The values of ω, D*, and Rd for the XGSB backfill were compared to those for soil-bentonite backfills in previous studies. A linear equation was presented to evaluate the correlation between ω and solute concentration in a semi-logarithmic scale. Finally, the advantages of considering membrane behavior in the design of slurry trench wall was discussed with the aid of an example analysis based on the measured ω and D* for the SB and XGSB backfill.

A comparative study to determine seismic response of the box culvert wing wall under influence of soil-structure interaction considering different ground motions

The present study deals with evaluation of the effects of different ground motions, backfill-structure interaction (BSI) and soil-structure interaction (SSI) on dynamic response of a box culvert wing wall. In obtaining numerical results, five different earthquake records with different frequency contents, five different backfill types and four different subsoil types are taken into account. Firstly, a finite element model (FEM) and three analytical models are proposed for analysis of the wing wall-backfill system under fixed-base case, and these fixed-base models are compared with each other through both modal analysis and displacement time-history analysis under the assumption of linear-elasticity. After validating the ability of the FEM approach, by extending the fixed-base FEM to take account of elastoplastic behavior of soil and SSI, a three dimensional (3-D) model has been described, and 3-D nonlinear analyses have been carried out in time domain. The numerical results show that the seismic response of the wing walls are affected remarkably by the SSI, BSI and frequency content of the earthquake.

Performance Improvement of Underground Pipe Line Foundation Using Recycled Materials

According to the Seoul City survey, about 84% of the occurrence of ground subsidence was the main cause of damage to the sewer pipe, and it was related to the aging of the sewage pipe foundation and the sewage pipe itself. To reduce the damage, a combination of field-assembled recycled plastic foundation and a fluid backfill material was applied. The bearing capacity, settlement, and pipe safety factor were evaluated for comparison with the existing crushed stone foundation and concrete foundation. The change in settlement was relatively small, according to the type of backfill used in the analysis. As for the support method used when selecting the foundation for the sewage pipe for a rigid pipe, it was found that applying a fixed type rather than a free type improved the safety of the pipe. The field-fabricated recycled plastic foundation has less material rigidity than the concrete foundation, but to compensate for this, applying the fluid backfill using 2% to 4% cement had the effect of increasing adhesion and enhancing the strength of the backfilling material, thus increasing the safety of the installed pipe.

Influence of backfill type on the load-bearing performance of GRS bridge abutments

The influence of backfill type and material properties on the performance of field-scale geosynthetic reinforced soil (GRS) abutment models is investigated. Two alternative types of backfill as recommended in the Federal Highway Administration (FHWA) guidelines (called open-graded and well-graded) were used to build two field-scale model abutments and compare their load-bearing performance under a loading beam. Results are presented and discussed relative to the loading beam settlement, facing deformation and reinforcement strains. The well-graded backfill was found to result in smaller beam settlements and facing lateral deformations, especially at smaller loads that were comparable to service load levels. However, it was significantly faster and easier to compact the open-graded aggregate to the unit weight recommended in the guidelines. Nevertheless, performances of both abutment models were found to be satisfactory relative to the limiting requirements on the beam settlement and facing deformations at service load levels.

Seismic behavior of geosynthetic-reinforced retaining walls backfilled with cohesive soil

This study investigates the seismic performance of geosynthetic-reinforced modular block retaining walls backfilled with cohesive, fine grained clay-sand soil mixture. Shaking table tests were performed for three ½ scaled (wall height 190 cm) and ¼ scaled model walls to investigate the effects of backfill type, the influence of reinforcement length and reinforcement stiffness effects. The El Centro and Kobe earthquake records of varying amplitudes were used as base acceleration. Displacement of the front wall, accelerations at different locations, strains on the reinforcements, and the visual observations of the facing and the backfill surface were used to evaluate the seismic performance of model walls. The model walls were subjected to rigorous shaking and the walls did not exhibit any stability problems or signs of impending failure. The maximum deformations observed on the models with cohesive backfill was less than half of the deformation of the sand model. The load transfers between the geogrid and cohesive soil was comparable to that of sand and hence the needed reinforcement length was similar as well. As a result; the model walls with cohesive backfills performed within acceptable limits under seismic loading conditions when compared with granular backfilled counterparts.

Diffusion through soil-bentonite backfill from a constructed vertical cutoff wall

Diffusion coefficients were measured for soil-bentonite (SB) backfill sampled from a constructed vertical cutoff wall in Pennsylvania, USA. The backfill consisted of lean clay (the base soil) combined with bentonite-water slurry containing 5–6% sodium bentonite, resulting in a total bentonite content of ~1%. Ten dialysis leaching tests (DLTs) were conducted to measure apparent diffusion coefficients (Da) for chloride (Cl−) diffusion through the lean clay-bentonite backfill. In addition, model sand-bentonite backfills (total bentonite content = 4.7%) were prepared in the laboratory, and eight DLTs were performed for comparison with the field-sampled backfill and the diffusion literature. Both backfill types were tested with monovalent and divalent salt solutions (KCl and CaCl2), over a wide range of concentrations (60–350 mM). Despite the difference in bentonite content, values of Da were similar for the two backfills. Changes in Da with increasing average Cl− concentration were relatively minor, increasing by less than half an order of magnitude over the wide range of salt solutions, likely due to the low percentages of bentonite (<5%) in both backfills. Thus, for SB backfills with bentonite contents <5%, Da appears to be relatively insensitive to backfill composition, salt type and concentration.

Impact of In Situ Soil in Soil-Bentonite Cutoff Wall Backfill on Compressibility and Hydraulic Conductivity

Soil-bentonite cutoff walls, consisting of excavated in situ soil and bentonite as backfills, are used extensively as vertical barriers for groundwater pollution control. Sand mixed with high-quality natural sodium bentonite (NaB) is commonly used as a research object to investigate the hydraulic and compression properties of soil-bentonite backfills. However, pure sand could rarely be found in real conditions, and natural NaB may not be available readily in some countries such as China, India, and Turkey. This paper presents a comprehensive laboratory investigation on the compressibility and hydraulic conductivity (k) of soil-bentonite backfills created by simulated in situ soil and low-quality sodium activated calcium bentonite (SACaB). The simulated in situ soils are prepared using sand-natural clay mixtures with sand to natural clay mass ratios ranging from 0.5 to 6.0, and the bentonite content (BC) in the base mixture ranges from 0 to 15%. The result indicates that BC dominates the compression index (Cc) of the backfill, and a unique relationship between void ratio at effective vertical compression stress of 1 kPa and compression index is proposed for various types of soil-bentonite backfills. An increase in either BC or clay size fraction (CF) in simulated in situ contributes to reducing k, but the impact of CF in simulated in situ soil on k tends to be insignificant for backfill with BC higher than 6%. A new characteristic parameter based on the concept of void ratio of bentonite (eb), named apparent void ratio of clay size fraction (eC), is developed for predicting soil-bentonite backfills created by in situ soils and bentonites with various contents.

Co-disposal of magnesium slag and high-calcium fly ash as cementitious materials in backfill

Waste minimization is a major approach whereby many industries decrease environmental pollution and promote cleaner production. To achieve sustainable development, a novel idea is proposed herein to recycle magnesium slag (MS) and high-calcium fly ash (FA) into cementitious materials which are then mixed with aeolian sand (AS) to produce a type of paste backfill (MFPB) material that can be used in the mining industry. The rheological and mechanical properties of backfill materials with different FA contents were investigated. The results reveal that: (1) fresh MFPB mortars with different proportions conformed to the Herschel–Bulkley model. The yield stress initially decreased, and then increased with rising FA content. When the FA content was less than 20 wt%, the rheology of the MFPB surpassed that of the pure MS mortar, and an FA content of 10 wt%, yielded the best rheological properties of the fresh MFPB mortar. The mini-slump value, which was between 108 mm (MS-FA0) and 141 mm (MS-FA10), first increased and then decreased with increasing FA content. (2) The unconfined compressive strength (UCS) increased with extended curing times and FA contents, as well as the early-age strength development, which accelerated with increasing FA content. The UCS at 28 d escalated from 2.607 MPa (MS-FA0) to 7.491 MPa (MS-FA40). (3) The microstructure of the MFPB samples was discovered to agree with the UCS results. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were conducted to investigate the hydration products of the MFPB samples. The hydration mechanism of the MS and FA mixture was discussed, and the former was less reactive when used individually, although its reactivity increased with the addition of high-calcium FA. CaO dissolution in the MS and FA led to the generation of Ca(OH)2, which was a prerequisite for the successive pozzolanic reaction between the MS and FA. This study investigated the feasibility of the co-disposal of MS and FA, which could significantly promote a cleaner mineral production, and mining industry, when used together with backfill technology.