Search results for: Latest H19-461_V1.0 Exam Questions Vce 🏯 H19-461_V1.0 Labs 🐒 H19-461_V1.0 New Study Plan 🙊 Search for ✔ H19-461_V1.0 ️✔️ on 「 www.pdfvce.com 」 immediately to obtain a free download 🧎H19-461_V1.0 Best Vce
-
Prediction Of Groundwater Impacts For Excavations
Groundwater inflow and levels associated with excavations are important considerations for construction and operation of the completed development. Drawdown associated with excavation has potential to result in settlement, impacts on vegetation and ecosystems and the distribution of existing groundwater contamination. Inflows to excavations need to be dealt with including possible need for treatment prior to release to the surface water system.
The paper presents methods which can be used to address a range of groundwater issues associated with excavation drawing upon closed form analytical methods. The methods presented are illustrated with examples drawn from practice.
Topics discussed include:
- Prediction of maximum groundwater level over the design life of a project
- Prediction of the rate of groundwater inflow to an excavation
- Prediction of groundwater level drawdown associated with excavation.
-
Analysis of soil-foundation-structure interaction to load transfer mechanism in reinforced piled embankments
The scope of this paper is the analysis of a piled embankment reinforced geosynthetic with discrete element method and soil model at the microscopic level. The vertical stress distribution, load transfer mechanism, efficacy, differential settlement and tension in geosynthetic were chosen for comparison and interpretation of results. The contribution of tensioned membrane effect by geosynthetic reinforcement to load transfer mechanism is elucidated through the numerical analysis, which is generally neglected in the most current design procedures. Additionally, a new analytical approach was proposed to analyze the load-deflection behavior. This method is the results of the combination of the tensioned membrane theory and soil arching theory, thereby providing a more suitable design approach and believed to be a useful tool for engineers in designing the soil-geosynthetic system. The validity of the analytical method is compared to the numerical results by using the discrete element method. Thus, the results of this study are intended to provide some guidelines for designers and to bring insight about the interacting mechanisms into the design process.
-
Combined Effects Of Eggshell Powder And Hydrated Lime On The Properties Of Expansive Soils
This study involves the utilization of eggshell powder (ESP) as a supplementary additive to lime stabilization of expansive soil and evaluates its potential in enhancing the performance of expansive soil treated with lime. Eggshell is a waste material obtained from several sources. Some of the challenges associated with dumping eggshell are odour, insect growth, disposal costs and availability of disposal sites. In order to reduce these environmental issues, eggshells can be processed into ESP and play a role as a soil stabilizing agent. Calcium oxide is considered to be the main ingredient of the ESP. Therefore, an experimental program is carried out to test a mixture of kaolinite, bentonite and Sydney fine sand, which is simulated to be as an artificial expansive soil. The eggshell powder was used as an additive to 5% lime in four percentages of 5%, 10%, 15% and 20% by total dry weight of the soil mass. Results of linear shrinkage, proctor compaction, and unconfined compressive strength tests after various curing time are presented in detail and compared with untreated soil samples. The outcomes of these experimental investigations indicated that the combination of eggshell powder and hydrated lime led to a further decrease in linear shrinkage and the maximum dry density of expansive soil samples. It was found that the improved geotechnical characteristics were more pronounced for 5% ESP treated expansive soil. At this percentage, the compressive strength at failure and the corresponding strain increased slightly by 18% and 9%, respectively, compared to the untreated expansive soil after 28 days of curing. Moreover, in comparison with lime (5%) only stabilized expansive soil, the combined lime (5%) and ESP (5%), induced approximately 15% build-up in the compressive strength of samples. Based on the reasonable laboratory test results, this addition is recommended to improve the shrinkage properties and stabilize the expansive soils where the high performance of subgrade is neglected.
-
Laboratory Investigation On The Use Of Vertical Drains To Mitigate Mud Pumping Under Rail Tracks
The build-up of excess pore water pressure (EPWP) in undrained soft subgrade under repeated rail loads is the key mechanism causing soil to fluidise, consequently yielding slurry tracks (i.e., mud pumping). This issue has substantially reduced transport efficiency associated with immense cost for track maintenance though considerable effort has been made over the past years. Therefore, this study is carried out to investigate how prefabricated vertical drains (PVDs) can be used to mitigate the accumulated EPWP and associated mud pumping. A series of cyclic triaxial tests including undrained (i.e., without PVDs) and PVD-assisted drained soils are conducted, and their results are compared to evaluate the effect of PVDs on cyclic soil behaviour. In this investigation, subgrade soil collected from a mud pumping site is used while loading parameters including the frequency, confining pressure and cyclic stress ratio (CSR) are considered with respect to heavy rail load condition in the field. The results show that PVDs can help dissipate effectively the accumulated EPWP, thus mitigating soil fluidisation. The current study shows that for undrained condition, lower frequency loading (i.e., slower trains) takes a smaller number of cycles to cause soil failure, whereas for drained cases (i.e., PVDs-assisted specimens), an opposite trend is observed. The study proves that installing PVDs into shallow layer (i.e., 3-5 m depth) is an effective approach to stabilise soft subgrade soil under rail tracks.
-
Substance and mass properties for the design of engineering structures in the Hawkesbury Sandstone
The Hawkesbury Sandstone dominates the Sydney region, both from the viewpoint of engineering structures and the natural topography. This Formation thickens from its western and southern outcrop margins in the Blue Mountains and Illawarra to about 290 m near the Hawkesbury River.
This article is an expansion of one published in 1985 in the volume “Engineering Geology of the Sydney Region”. The original document concentrated on the engineering properties of the intact sandstone (i.e. the ‘substance’) whereas this article covers both substance and rock mass parameters. Much of the original information on substance parameters is reproduced here with additions from papers published in the volume “Sandstone City” published in 2000 by the Geological Society of Australia. The rock mass data are taken from papers published since 1985.
-
Landslide inventory, susceptibility, frequency and hazard zoning in the Wollongong and wider Sydney Basin Area
The University of Wollongong Landslide Research Team has been working on the development of GIS-based Landslide Inventory, Susceptibility and Hazard Zoning projects for over 15 years. To undertake the zoning work we use knowledge-based methods including Data Mining techniques which are facilitated within a GIS framework. This work is ongoing, and as with this paper, there are two main aims; firstly for those smaller subregions of Sydney where considerable data have been obtained and the landslide inventory development is comprehensive, increasingly more reliable modelling, analysis and synthesis is being done, and secondly, for the entire 31,000km2 geological extent of the Sydney Basin region where the available data are relatively small scale and the process of developing the landslide inventory is in the early stages, preliminary studies which are described as ‘proof of concept’ have been completed and are reported herein. The most advanced sub-region is a large portion of the Illawarra Escarpment within the Wollongong Local Government Area (LGA). Another advanced sub-region is the Picton area within the Wollondilly LGA. All the while, input data is being refined and improved in particular with the advent of Airborne Laser Scan derived DEM’s and the ongoing development and populating of Landslide Inventories. In tandem with refined input data, computing capabilities are also rapidly evolving and this is enabling ever growing terrain modelling capacity. With higher resolution input data for the Sydney Basin project, including a more rigorous Landslide Inventory which is already well under development, higher resolution geology information and possibly even a better or more recent DEM, the regional yet large scale GIS-based Susceptibility modelling outcomes are likely to be suitable for use at Local Government Planning levels. Furthermore, susceptibility modelling at a national scale to identify preliminary or ‘first pass’ binary type (i.e. in/out) areas for further assessment is also achievable in the very near future.
-
Structural Reliability Of Retaining Walls Designed To AS 4678 For Permanent, Imposed And Seismic Loads
Part 1 – External Stability
AS 4678-2002 Earth retaining structures may be used to design gravity retaining walls (including reinforced soils, segmental gravity retaining walls and cantilever retaining walls). This paper compares the structural reliability of retaining walls designed to AS 4678, to those designed using other codes, British Code of Practice CP2 and the National Concrete Masonry Association (USA) method of designing reinforced soils.
Part 2 – Earthquake
AS 4678 Appendix I sets out the options for designing retaining walls for earthquake, based on a classification method consistent with AS 1170.4-1993 (which is now superseded) and simplified rules. Some combinations lead to non-conservative design, but only where “failure would result in not more than moderate damage and not more than minimal loss of access”, or “failure would result in moderate damage and loss of services” with low or medium seismicity.
-
An Engineering Assessment Of The Strength And Deformation Properties Of Brisbane Rocks
The use of standard relationships between point load index (Is(50) ), Uniaxial Compressive Strength (UCS) and elastic modulus values is commonly used within the geotechnical engineering community. The validity of these relationships is examined using data from several major projects carried out in Brisbane recently. Additionally the methods of Point Load Index testing is examined, particularly the impact of the direction of testing. It is established that in extremely low to low strength rocks, axial tests are likely to produce a higher point load index value. Based on our data set, the use of the standard multiplier of 24 (Broch and Franklin, 1972) to obtain UCS from Is(50) values is shown to be unconservative for several rock types. In terms of modulus values, in comparison with published recommendations (eg Deere, 1968), the established ratios are generally within the 100-500 times UCS ratio quoted, however the value for the DW metasediments is considerably higher.
-
Uncertainty, economic risk analysis and risk acceptance criteria for mine subsidence
There are often differences in ‘expert opinions’ of what constitutes appropriate design parameters for determining the level of stability of the existing pillars of old coal mine workings. For example, there is seldom 100% certainty about the value of any design parameter. Instead there are varying degrees of confidence (or belief) for each possible design value. This uncertainty in design parameters can be represented by probability distributions. The inclusion of such probabilistic information into a probabilistic risk analysis will enable the probability of failure to be estimated. To illustrate the utility of risk analysis for decisions taken with uncertainty, a probabilistic risk analysis has been conducted to assess the uncertainty of design parameters on the level of stability of existing pillars within a disused coal seam beneath a proposed surface development in the Newcastle area. The case study considers dimensional and level of inundation uncertainties. This case study provides a preliminary framework for a risk-based approach to decision- making for a geotechnical system subject to high uncertainties. The outcomes of the risk analysis are probability of failure and annual economic risks (expected losses per year). The paper will describe the steps taken in the risk assessment, risk acceptance criteria and how results from a risk analysis may be interpreted by a decision-making development consent authority.
-
Structure nonlinearity and response of laterally loaded piles
In light of a generic limiting force profile (LFP), closed-form solutions for laterally loaded free- and fixed- head piles in elastic-plastic media have been developed, and implemented by the first author into a spreadsheet program called GASLFP. The solutions offer an expeditious and sufficiently accurate prediction of response of lateral piles. Conversely, they allow input parameters to be deduced using measured pile response, as has been conducted for over 70 test (elastic) piles to date. Nevertheless, structure nonlinearity of pile body is an important issue at a large deflection.
In this paper, a semi-empirical approach is established to capture pile response owing to structural nonlinearity. Expressions were provided for gaining cracking moment Mcr, flexural rigidity of cracked cross section EpIp, and ultimate bending moment Mult. Against measured response of two laterally loaded single piles, back-estimation indicates that (1) the parameters for elastic piles are quite consistent with the previous findings for piles in sand and clay, (2) The proposed variations of Mcr, EpIp and Mult for nonlinear piles provide good prediction of the pile response against measured data and (3) the modulus of rupture kr of 16.7 (clay) and 33.0(sand) are close to those adopted for structural beams, although a very high kr of 62.7 (thus resulting in higher Mcr) for a pile in sand was deduced (shown elsewhere). The use of the kr for beams would render pile deflections of the later pile to be significantly overestimated. The conclusions may be incorporated into design of laterally loaded piles.