Applied Research on Dynamic Replacement Method in Tailings Residue Subgrade Reinforcement

2013 ◽  
Vol 639-640 ◽  
pp. 943-946
Author(s):  
Jiao Long He ◽  
Yong Zhou ◽  
Zhong Ai Jiang
Keyword(s):  
Applied Research ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Testing ◽  
Standard Penetration Test ◽  
Load Test ◽  
Test Results ◽  
Replacement Method ◽  
Dynamic Replacement ◽  
Testing Experiment

Based on the reinforcing mechanism of dynamic replacement method ,this article put forward the construction parameters and measures of dynamic replacement method , combining with the result of actual engineering field testing experiment. The field load test, standard penetration test and pore water pressure test results show that the characteristic value of subgrade bearing capacity is more than 130 kpa when the tailings residue subgrade has been managed with dynamic replacement method, providing references for applied research on dynamic replacement method in tailings residue subgrade reinforcement.

Application Study on Dynamic Compaction Technology in Mine Tailings Foundation Reinforcement

2012 ◽  
Vol 170-173 ◽  
pp. 3054-3058
Author(s):  
Jiao Long He ◽  
Zhong Ai Jiang
Keyword(s):  
Mine Tailings ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Testing ◽  
Standard Penetration Test ◽  
Dynamic Compaction ◽  
Application Research ◽  
Loading Test ◽  
Application Study ◽  
Compaction Method

The dynamic compaction parameters and measures for tailings foundation are proposed based on actual engineering field testing result.Results of field loading test,standard penetration test and pore water pressure test show that when tailings foundation is reinforced by dynamic compaction method,the bearing capacity value is greater than 130kpa.These provide a reference to application research of dynamic compaction in the tailings foundation.

scholarly journals Perbandingan Pengujian Konsolidasi Menggunakan Alat Rowe Cell dan Oedometer pada Tanah Lanau Lunak

2020 ◽  
Vol 22 (2) ◽  
pp. 149-155
Author(s):  
Iskandar ◽  
Rabiya
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Samples ◽  
Soil Parameters ◽  
Soil Consolidation ◽  
Test Results ◽  
Soft Soils ◽  
Better Than ◽  
Rowe Cell

Soil consolidation testing using an oedometer and rowe cell. Oedometers are often used on clay and soft soils. However, in the development of the rowe cell device, the results of lowering soft soil were better than the oedometer. The advantage of this rowe cell is that it can determine the saturation value of the soil samples tested. The rowe cell tester can measure the pore water pressure at the beginning and end of each consolidation stage. This rowe cell can provide suitable settlement for soft soils. This consolidation test to obtain soil parameters such as Cv and Cc by using the rowe cell tool. After that, from the test results, the two tools were compared.

scholarly journals Impact of the moisture content in medium sands on CPTU test results

2016 ◽  
Vol 48 (3) ◽  
pp. 221-231 ◽  
Author(s):  
Łukasz Zawadzki ◽  
Marek Bajda
Keyword(s):  
Moisture Content ◽  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Degree Of Saturation ◽  
Test Results ◽  
Time Dynamic ◽  
Tip Resistance ◽  
The Impact ◽  
Resistance Value

Abstract Soils occurring in the soil “active zone” are in contact with the surface and are directly influenced by external factors (mainly climatic changes) that cause variation in their parameters over time. Dynamic and uncontrolled changes of soil properties e.g. due to rainfall and evapotranspiration processes may affect field test results leading to the misinterpretation of the obtained data. This paper presents investigations on the influence of moisture content changes in sandy soils on CPTU results. For this purpose, a field ground model has been constructed and five CPTU tests with a different moisture content of soil were carried out. During the investigations, the tip resistance (qc), friction on sleeve (fs), and pore water pressure (u2) were measured. Moreover, a TDR probe was applied to determine the distribution of the moisture content in the studied soil columns. Differences between CPT results obtained in saturated and unsaturated soils have been shown. Furthermore, a simple equation to correct the tip resistance value due to the impact of the degree of saturation has been proposed.

Improving engineering properties of mature fine tailings using Tubifex

2020 ◽  
Vol 47 (7) ◽  
pp. 812-821
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
Test Results ◽  
Sulfate Content ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
The Mean ◽  
Solids Content

The present study investigated the effects of Tubifex (Oligochaeta: Tubificidae) treatment on the dewatering process of mature fine tailings (MFT). Experiments testing the survival rate showed that Tubifex can survive at 20 °C and 4 °C. MFT with initial solids content (Sc) of 30% of total mass were treated in 11 settling columns by three Tubifex densities, 1400, 2000 and 4200 individuals·m−2. Test results showed that the mean survival rate at 20 °C and 4 °C on the 28th day stayed around 85%. Tubifex enhanced MFT dewatering by providing compacted tailings with 11.6% and 66.7% higher Sc and undrained shear strength compared with nontreated tailings. Tubifex accelerated pore water pressure dissipation. Tubifex did not affect the chemical composition of tailings except for a decrease in sulfate content. The Sc of tailings treated by Tubifex increased by 67.4% within nine months, which was 129% greater than the Sc increase of the nontreated tailings after 11 months.

Theoretical prediction of rutting in flexible pavement subgrades

1992 ◽  
Vol 29 (5) ◽  
pp. 765-778 ◽  
Author(s):  
D. V. Ramsamooj ◽  
R. Piper
Keyword(s):  
Pore Water ◽  
Critical State ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Permanent Deformation ◽  
Flexible Pavement ◽  
Load Test ◽  
Model Parameters ◽  
Silty Clay ◽  
Rate Of Development

The theoretical model for predicting the cyclic response of soils is extended to handle the generation and dissipation of pore-water pressures and to predict the rutting of the subgrade of a flexible pavement. The model utilizes multiyield surfaces and the concepts of critical state mechanics to predict the permanent deformation of the subgrade under vehicular loading. The theoretical solution also considers the effects of the drainage characteristics of the subgrade soil on the rate of development of the permanent deformation. Experimental verification of the model concepts are presented for a drained cyclic load test on Ottawa sand and for undrained cyclic loading on Newfield clay using published experimental data. An illustrative example is given for the prediction of rutting in a silty clay subgrade. The model parameters for the silty clay are obtained from triaxial and consolidation tests. These parameters are then put into a computer program that determines the rut depth, pore-water pressure, and the ratio of the vertical deformation and the rut depth as functions of the number of vehicular loads for a flexible pavement for various conditions of drainage ranging from undrained to fully drained. The role of the coefficient of consolidation of the subgrade in controlling the rate of development of the rut depth is highlighted. Key words : critical state soil mechanics, multiyield surfaces, rutting, silty clay subgrade, drainage, vehicular loading.

scholarly journals Effects of Geosynthetic Reinforcement on Tailings Accumulation Dams

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 2986
Author(s):  
Changbo Du ◽  
Lidong Liang ◽  
Fu Yi ◽  
Ben Niu
Keyword(s):  
Comparative Analysis ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Earth Pressure ◽  
Good Choice ◽  
Tailings Dam ◽  
Test Results ◽  
Reinforcement Effect ◽  
Tailings Dams ◽  
Over Time

Owing to the complexity of current reinforcement mechanisms, test results from existing models alone cannot provide a basis for the design of new tailings dam reinforcement projects. On-site reinforced tailings accumulation dam testing is thus required to further understand the reinforcement mechanism. In this study, the influence of reinforcement on tailings dams and the variation law of pore water pressure (PWP) and internal pressure (IP) in the dam body after slurry discharge were analysed, and a comparative analysis was performed. The results showed that during the field test, the PWP and internal earth pressure of the accumulation dam after grouting gradually increased over time. Reinforcement can greatly reduce the PWP and IP of the reinforced dam; compared with geotextiles, the reinforcement effect of geogrids is slightly greater. Based on these results, we conclude that geosynthetics are a good choice for strengthening tailings accumulation dams.

scholarly journals Initial Hypotheses for Modeling and Numerical Analysis of Rockfill and Earth Dams and Their Effects on the Results of the Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad Rashidi ◽  
Habib Rasouli
Keyword(s):  
Bulk Modulus ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Numerical Analyses ◽  
Earth Dams ◽  
Analysis Method ◽  
Replacement Method ◽  
Behavioral Parameters ◽  
High Dams ◽  
Parametric Analyses

Since the behavior of earth dams is unreliable in different stages of construction, impounding, and exploitation, this matter is an unavoidable and essential issue with regard to the serious dangers caused by the failure of these important structures. It is crucial to evaluate the behavior of dams and examine the consistency between the carried out analyses and the behavioral parameters under different conditions in the lifespan of dams due to the uncertainty of the principles and hypotheses which have been adopted to analyze these structures. This objective will be accomplished through the help of correct numerical analyses. A series of hypotheses are adopted to simplify the parametric analyses before starting these analyses. The aim of this research is to develop and discuss these hypotheses. And so, the number of elements and their effects on the results of analyses were examined through the consolidation of unsaturated soil method, the compressible fluid method, correlated analysis, and uncorrelated analysis. It became clear after the numerical analyses that correlated analysis is a more precise method in comparison with the uncorrelated analysis method. However, this method is not economical when it comes to high dams and the replacement method is the uncorrelated analysis. Furthermore, the displacements are not that sensitive to the bulk modulus of water while the maximum settlement of the dam transfers from the middle of the dam’s core to a location higher than that the core as the bulk modulus of water increases. However, pore water pressure is very sensitive to the bulk modulus of water.

scholarly journals Vertical and horizontal permeability measurements in organic soils

2015 ◽  
Vol 47 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Edyta E. Malinowska ◽  
Alojzy Szymański
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Flow Characteristics ◽  
Vertical Direction ◽  
Organic Soil ◽  
Organic Soils ◽  
Test Results ◽  
Consolidation Process ◽  
Consolidation Model ◽  
Horizontal Permeability

Abstract The paper is referring to vertical and horizontal laboratory permeability measurements in soft organic soils. The estimation of anisotropic permeability in soft organic soils, as peats, requires to use a special apparatus and the knowledge of proper analysis of the test results. During loading the void ratio decreases substantially that causes the changeability of the permeability. The change of permeability during the compression is very important because of the influence of the consolidation co-efficient. Initial strain in soft organic soils appears very quickly, just after loading, and brings immediately the decrease of permeability. In most of the estimations, it is assumed that during the consolidation process the water flows just in the vertical direction. In soft organic soils, like peats, the consolidation theory should consider the changes of mechanical and physical properties in consolidation period, in both directions. The direct measurement of vertical and horizontal permeability of organic soil and the non-Darcian flow theory may be of considerable importance in estimating pore water pressure dissipation, and settlement rates in the consolidation model. In the paper, the method of investigation and the test results of the vertical and horizontal permeability are presented. The Modified Rowe Cell Set for obtaining consolidation and flow characteristics in different directions is used.

Field Testing: The Standard Penetration Test

1986 ◽  
Vol 2 (1) ◽  
pp. 21-26 ◽  
Author(s):  
S. Thorburn
Keyword(s):  
Field Testing ◽  
Standard Penetration Test ◽  
Cohesive Soils ◽  
Test Results ◽  
Penetration Test ◽  
Test Procedures ◽  
Weak Rocks ◽  
Fine Grained ◽  
Introductory Lecture ◽  
Strength And Stiffness

AbstractThis introductory lecture discusses the international use of the standard penetration test (SPT) and presents the proposals for International Reference Test Procedures. The application of the SPT as a means of assessing the strength and stiffness of weak rocks is mentioned together with the reliance upon the test at the present time for estimating the liquefaction potential of saturated fine grained non-cohesive soils. The various aspects of the execution of the SPT are discussed which can provide variable and unrepresentative values of resistance (N values).The principle of measuring energy losses and making adjustments to the N values is introduced as a basis for ensuring comparability of test results.Reference is made to the general descriptions of the SPT given in BS 5930:1981 and to the lack of clear guidance in this British Standard.

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