scholarly journals ANALISIS PENURUNAN PADA TIMBUNAN DENGAN PREFABRICATED VERTICAL DRAIN (PVD) MENGGUNAKAN DATA HASIL UJI CPTu

2020 ◽  
Vol 3 (1) ◽  
pp. 69
Author(s):  
Tomy Gunawan ◽  
Alfred Jonathan S ◽  
Ali Iskandar
Keyword(s):  
Pore Pressure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Parameters ◽  
Cone Penetration ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain ◽  
Soil Settlement ◽  
Hydrostatic Level ◽  
Settlement Analysis

Investigation of soil is important to do in the planning of building construction such as foundations, piles, roads, etc. To find out the bearing capacity and parameters of the soil where a building will be built. Investigation of the soil can be done in various ways, one of which uses an electrical cone penetration test with pore water pressure. In the embankment project for the calculations on the soil so that it can be known about the settlement in soil and the length of time it reaches the hydrostatic level. Cone penetraton test is reqired and the results produce data in the form of cone resistance (qc), blanket friction (fs) and pore pressure (u) which will be processed in the CPET-IT program in order to produce soil parameters that will be used for soil settlement analysis. To find out the settlement of embankment soil, it will be supported by finite difference program. Results of studies on general is to find the effectiveness of embankment using prefabricated vertical drain (PVD) and without prefabricated vertical drain (PVD).AbstrakPenyelidikan terhadap tanah penting untuk dilakukan pada perencanaan konstruksi bangunan seperti pondasi, timbunan, jalan, dll. Untuk mengetahui daya dukung dan parameter-parameter tanah tempat akan dibangunnya sebuah bangunan Penyelidikan tanah dapat dilakukan dengan berbagai macam cara salah satunya adalah menggunakan  uji sondir elektrik dengan tekanan air pori. Pada proyek timbunan memerlukan perhitungan pada tanahnya agar dapat diketahui besarnya penurunan pada tanah dan lama waktu tanah mencapai keadaan hidrostatis. Sehingga dilakukan uji sondir secara elektrik dan dari hasil uji sondir menghasilkan data berupa tahanan konus (qc), gesekan selimut (fs) dan pore pressure (u) yang akan diolah kedalam program CPET-IT agar menghasilkan parameter-parameter tanah yang akan digunakan untuk analisis penurunan pada tanah.Untuk mengetahui besarnya penurunan pada tanah timbunan maka akan dibantu program berbasis elemen higga. Hasil studi secara umum menunjukkan seberapa besar efektivitas pada timbunan dengan menggunakan prefabricated vertical drain (PVD) dan tanpa prefabricated vertical drain (PVD).

scholarly journals Physical Model Test for Soft Soil With or Without Prefabricated Vertical Drain with Loading

2018 ◽  
Vol 4 (8) ◽  
pp. 1809
Author(s):  
Dao Huu Do ◽  
Nguyen Thi Phuong Khue ◽  
Phan Khac Hai
Keyword(s):  
Numerical Simulation ◽  
Physical Model ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Physical Model Test ◽  
Soil Parameters ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain ◽  
Before And After

The paper builds a physical model of testing in the laboratory with the parametric tempered glass box 0.5  0.5 1.2 m (length  width  depth) containing saturated clay to study the settlement and consolidation when loading increased gradually over time. The research covers herein to present the monitoring of settlement and pore water pressure, settlement calculation, numerical simulation using PLAXIS software V8.2 based on the results of soil physical and mechanical tests before and after loading in case of having or not prefabricated vertical drain (PVD). In case of no PVD, the calculation and numerical simulation using the soil parameters before loading have the differential settlement from the monitoring data, approximately 3.86 mm (10.45%), 0.41 mm (1.11%) respectively. Meanwhile, the deviation in the case using data after loading is about 2.29 mm (6.20%), 0.21 mm (0.56%) respectively. In case of PVD, the calculation and numerical simulation with the testing result of before loading deviation from the settlement monitoring by subsidence meter is 2.91 mm (7.88%), 44.42 mm (120.28%), calculation and simulation with the testing result of after loading deviation is 0.80 mm (2.17%), 1.26 mm (3.41%). In the case of having PVD, the difference in calculation, subsidence observation, and numerical simulation between the mechanical properties before and after loading is significant, when using the mechanical data after loading then the results are quite close to the subsidence of observation and simulation rather than before loading. 

scholarly journals Numerical Modelling of Prefabricated Vertical Drain for Soft Clay Using ABAQUS

2015 ◽  
Vol 773-774 ◽  
pp. 1502-1507
Author(s):  
Saiful Azhar Ahmad Tajudin ◽  
Mohd Fairus Yusof ◽  
I. Bakar ◽  
Aminaton Marto ◽  
Muhammad Nizam Zakaria ◽  
...  
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soft Clay ◽  
Elastic Model ◽  
Clay Layer ◽  
Soil Consolidation ◽  
Consolidation Process ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain

Construction, buildings and infrastructure founded on soft clays are often affected by settlement problem. Therefore, Prefabricated Vertical Drain (PVD) is one of the best solutions to accelerate soil consolidation by shortening the drainage path. In this study, numerical investigation was carried out to pursue a better understanding of the consolidation behavior of soft clay improved with PVD. The consolidation process accelerated by PVD with surcharge of 50 kPa was analysed using the ABAQUS software by adopting an elastic model. The aim of this study is to compare the settlement and the required time to fully consolidate the soft soil at different drain spacings (1.0 m, 1.5 m and 2.0 m) for two different thickness of the clay layer. The results shows that the time required to completely consolidate the soft soil for 12 m and 20 m thickness of clay layer with different spacings are in the range of 3 months to 66 months. The settlement rate and excess pore water pressure dissipation are increased when the spacing of the drain closer.

Type of Slope Failure Identified from Pore Water Pressure and Moisture Content Measurements

2015 ◽  
Vol 744-746 ◽  
pp. 690-694
Author(s):  
Muhammad Rehan Hakro ◽  
Indra Sati Hamonangan Harahap
Keyword(s):  
Moisture Content ◽  
Pore Pressure ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Failure Process ◽  
Small Scale ◽  
Content Increase ◽  
Sudden Increase ◽  
Model Slope

Rainfall-induced landslides occur in many parts of the world and causing a lot of the damages. For effective prediction of rainfall-induced landslides the comprehensive understanding of the failure process is necessary. Under different soil and hydrological conditions experiments were conducted to investigate and clarify the mechanism of slope failure. The failure in model slope was induced by sprinkling the rainfall on slope composed of sandy soil in small flume. Series of tests were conducted in small scale flume to better understand the failure process in sandy slopes. The moisture content was measured with advanced Imko TDR (Time Domain Reflectrometry) moisture sensors in addition to measurements of pore pressure with piezometers. The moisture content increase rapidly to reach the maximum possible water content in case of higher intensity of rainfall, and higher intensity of the rainfall causes higher erosion as compared to smaller intensity of the rainfall. The controlling factor for rainfall-induced flowslides was density of the slope, rather than intensity of the rainfall and during the flowslide the sudden increase in pore pressure was observed. Higher pore pressure was observed at the toe of the slope as compared to upper part of the slope.

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 Mechanical response and pore pressure generation in granular filters subjected to uniaxial cyclic loading

2018 ◽  
Vol 55 (12) ◽  
pp. 1756-1768
Author(s):  
Jahanzaib Israr ◽  
Buddhima Indraratna
Keyword(s):  
Cyclic Loading ◽  
Pore Pressure ◽  
Pore Water ◽  
Mechanical Response ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Internal Erosion ◽  
Excess Pore Water Pressure ◽  
Excess Pore

This paper presents results from a series of piping tests carried out on a selected range of granular filters under static and cyclic loading conditions. The mechanical response of filters subjected to cyclic loading could be characterized in three distinct phases; namely, (I) pre-shakedown, (II) post-shakedown, and (III) post-critical (i.e., the occurrence of internal erosion). All the permanent geomechanical changes such, as erosion, permeability variations, and axial strain developments, took place during phases I and III, while the specimen response remained purely elastic during phase II. The post-critical occurrence of erosion incurred significant settlement that may not be tolerable for high-speed railway substructures. The analysis revealed that a cyclic load would induce excess pore-water pressure, which, in corroboration with steady seepage forces and agitation due to dynamic loading, could then cause internal erosion of fines from the specimens. The resulting excess pore pressure is a direct function of the axial strain due to cyclic densification, as well as the loading frequency and reduction in permeability. A model based on strain energy is proposed to quantify the excess pore-water pressure, and subsequently validated using current and existing test results from published studies.

Liquefaction Risk Assessment: Evaluation of Three Statistical Models

1996 ◽  
Vol 1526 (1) ◽  
pp. 79-85
Author(s):  
Khalid M. El Zahaby ◽  
M. S. Rahman
Keyword(s):  
Risk Assessment ◽  
Statistical Models ◽  
Historical Data ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Dissipated Energy ◽  
Soil Parameters ◽  
Seismic Action ◽  
Integral Measure ◽  
Discriminant Analyses

One approach to liquefaction risk assessment is based on a comparison of the earthquake and soil parameters for the site under study to those known to have either caused or not caused liquefaction at other sites during earlier earthquakes. In this study, three statistical models for liquefaction risk assessment are evaluated and compared. Both linear and nonlinear discriminant analyses are performed on the same set of historical data. It is found that the model with an energy-based formulation for the development of pore water pressure results in the least number of misclassified cases of liquefaction and nonliquefaction. The main conclusion derived from this study is that the use of an integral measure of seismic action, viz., dissipated energy, may result in a better assessment of liquefaction risk.

Numerical Simulation of Storage Tank Foundation Treated by Water Filling Preloading Method

2012 ◽  
Vol 204-208 ◽  
pp. 250-254
Author(s):  
Yan Mei Zhang ◽  
Xu Dong Zhang
Keyword(s):  
Common Ground ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Treatment Method ◽  
Soil Parameters ◽  
Three Dimension ◽  
Time Curve ◽  
Constrained Modulus ◽  
Water Filling ◽  
Preloading Method

The water filling preloading method is the common ground treatment method adopted to reinforce soft tank foundation. The influence laws of load speed, soil parameters on the reinforced effect of soft tank foundation were analyzed by the three-dimension finite element numerical analysis procedure. The research shows that the fovea deformation of single tank bottom under preload is similar to the pan bottom shape; the influence of soil constrained modulus on settlement is remarkable and it also affects the settlement time curve shape; when the constrained modulus is constant, with the permeability coefficient decreasing, the surface doming phenomenon around the tank foundation increases, and the range of upheaval is related to constrained modulus; the influence of loading function on the final settlement is very small, but the influence on pore water pressure is remarkable.

An effective stress model for creep of clay

1995 ◽  
Vol 32 (5) ◽  
pp. 819-834 ◽  
Author(s):  
Mohammed M. Morsy ◽  
D.H. Chan ◽  
N.R. Morgenstern
Keyword(s):  
Finite Element ◽  
Pore Pressure ◽  
Effective Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Surface Model ◽  
Interpolation Technique ◽  
Stress Integration ◽  
Integration Algorithms ◽  
Double Yield

An effective stress constitutive model to study the problem numerically of creep in the field is presented. A double-yield surface model for the stress–strain–time behaviour of wet clay is described. The model adopts the concept of separating the total deformation into immediate and delayed components. The yield surfaces employed are the modified Cam-clay ellipsoid and the Von Mises cylinder inscribed in the ellipsoid. The proposed numerical scheme incorporates the pore pressure based on field observations into a finite element analysis. An interpolation technique is used to determine the pore pressure at every element. A field example is presented to illustrate the interpolation technique procedure. The scheme not only avoids the complexity of making predictions of pore-water pressure, but also allows the analysis to be carried out in terms of effective stresses based on the actual observed pore pressure. Two stress integration algorithms based on the implicit calculation of plastic strain are implemented and tested for the double-yield surface model. A numerical simulation of stress-controlled drained creep tests confirms the numerical procedure. Key words : constitutive equations, creep, finite element, stress integration algorithms, effective stress approach, pore-water pressure.

scholarly journals Effect of Improvement and Application of Composite Prefabricated Vertical Drain Method in Marine Soft Ground: A Case Study

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Jianqing Jiang ◽  
Reqiang Liu
Keyword(s):  
High Speed ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Field Monitoring ◽  
Hyperbolic Model ◽  
Soft Ground ◽  
Prefabricated Vertical Drains ◽  
Prefabricated Vertical Drain

One of the commonly used techniques to improve marine soft ground is the drainage consolidation method by plastic board drains (PBDs). But some complex marine soft ground will cause construction inconvenience of PBDs in certain areas of these sites, thus affecting the improvement effect. An alternative possible approach to overcoming these deficiencies may be the combination of PBDs and sand wick drains (SWDs) (i.e., composite prefabricated vertical drains (CPVDs)) as vertical drainage channels in the same site. In order to verify the suitability and performance of this method in marine soft ground improvement, a case study was performed based on the field monitoring and construction of the marine soft ground of an intercity express railway project in China. The construction procedure using the CPVD system, the field monitoring instrumentation scheme, and the design of fill surcharge level were described, and the field monitoring data were presented. The settlement characteristics, dissipation features of pore water pressure, and the horizontal movement pattern were assessed. In addition, predictions of ultimate settlement, postconstruction settlement, and consolidation degree were discussed by applying a modified hyperbolic model. The results show that the marine ground improved by the CPVD system is suitable for the construction of intercity express railway and high-speed railway. The improvement construction period of complex marine soft ground will be greatly shortened by the proposed parallel construction programme. This work will provide technical supports and application reference for the improvement of the similar marine soft ground.

scholarly journals Discussion on Reinforcement Mechanism and Construction Technology of Pressurized Vacuum Preloading

2019 ◽  
Vol 136 ◽  
pp. 01036
Author(s):  
ZHUGE Ai-jun
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Tests ◽  
Good Effect ◽  
Construction Technology ◽  
Soil Consolidation ◽  
Vacuum Preloading ◽  
Pressure Transmission ◽  
Soil Settlement ◽  
Sand Cushion

Based on the basic theory of vacuum preloading, this paper proposes an good effect of pressurized vacuum preloading in which the high pressure gas results in tiny cracks between the air pressurized pipe and band drain. Therefore additional drainage paths are introduced to improve the permeability of soil and accelerate soil consolidation. But field tests show that the advantages of pressurized vacuum preloading are not obvious compared with conventional vacuum preloading, and the soil settlement, soil properties and vane shear strength are slightly lower than those by conventional vacuum preloading. The vacuum pressure transmission is analysed in the air pressurized pipe and band drain as well as the dissipation of pore water pressure in the soil during the pressurization process, it is concluded that the unsatisfactory reinforcement effect is mainly due to the sealing problem between the top of the air pressurized pipe and the sand cushion, and the overlap problem between the booster pipe and band drain.

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