Radial consolidation with vertical drains and general time-dependent loading

2009 ◽  
Vol 46 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Enrico Conte ◽  
Antonello Troncone
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Time Dependent ◽  
Case Histories ◽  
Vertical Drains ◽  
Excess Pore Water Pressure ◽  
Theoretical Methods ◽  
Consolidation Settlement ◽  
Degree Of Consolidation ◽  
General Time

A simple-to-use analytical solution for radial consolidation with vertical drains under equal strain conditions is presented in this paper. This solution accounts for the effects of soil smear, drain hydraulic resistance, and general time-dependent loading. A number of comparisons with other theoretical methods are shown to assess the accuracy of the proposed solution, both in terms of excess pore-water pressure and degree of consolidation settlement. Moreover, two case histories documented in the literature are analysed to evaluate the main parameters affecting radial consolidation in the presence of vertical drains.

The Influence Factors Analysis of Initial Excess Pore Water Pressure Caused by Construction of Shield Tunnels

2011 ◽  
Vol 268-270 ◽  
pp. 1295-1300
Author(s):  
Xin Jiang Wei ◽  
Wei Jun Chen ◽  
Gang Wei ◽  
An Yuan Liu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Influence Factors ◽  
Stress Transfer ◽  
Tunnel Lining ◽  
Excess Pore Water Pressure ◽  
Factors Analysis ◽  
Consolidation Settlement ◽  
Excess Pore

Excess pore water pressure caused by construction dissipated, resulting in consolidation settlement. The formula of initial excess pore water pressure around tunnel lining was deduced by stress relief theory, and its formula within the region of its distribution at any point was subsequently deduced by stress transfer theory. By comparing the measured data, shows that the calculated closed to the measured, and with the distance increased the initial excess pore water pressure decreased in a concave curve shape. When the depth of tunnel increased or the diameter decreased, would made initial excess pore water pressure between the tunnel bottom and tunnel center horizon around tunnel lining more different. At a certain depth, the mast initial excess pore water pressure above tunnel axis, away from the axis reduced; showing a similar PECK shape.

Preconsolidation pressures in intertill glaciolacustrine clay near Blaine Lake, Saskatchewan

1988 ◽  
Vol 25 (4) ◽  
pp. 831-839 ◽  
Author(s):  
E. Karl Sauer ◽  
E. A. Christiansen
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ice Thickness ◽  
Excess Pore Water Pressure ◽  
Stability Of Slopes ◽  
Preconsolidation Pressure ◽  
Insufficient Time ◽  
Degree Of Consolidation ◽  
Excess Pore

Soft, intertill, glaciolacustrine clays are of concern for stability of slopes and foundations. An intertill clay deposit between 32 and 54 m below the surface was continuously cored. Index properties were determined for 46 samples and 10 samples were tested on the oedometer. Stratigraphic evidence indicates that the glaciolacustrine clay (Blaine Lake Member), lying between the till of the Sutherland and Saskatoon groups, was glaciated three times. However, preconsolidation pressures of this intertill clay show the degree of consolidation is less than 20% based on a total stress from an estimated ice thickness extrapolated from the Cypress Hills. This low preconsolidation pressure suggests there was insufficient time for dissipation of excess pore-water pressure created by thickening of the advancing glacier. Key words: preconsolidation pressure, excess pore-water pressure, glaciers, intertill clay.

Finite Element Analysis for Subgrade Consolidation Settlement in Soft Soil

2013 ◽  
Vol 448-453 ◽  
pp. 1256-1259
Author(s):  
Feng Tan ◽  
Tai Quan Zhou
Keyword(s):  
Finite Element ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Soil Depth ◽  
Water Pressure ◽  
Soft Soil ◽  
Excess Pore Pressure ◽  
Excess Pore Water Pressure ◽  
Consolidation Settlement ◽  
Excess Pore

The two-dimensional finite element model for subgrade consolidation settlement analysis within soft soil pile is developed using ABAQUS. The numerical simulation on a highway subgrade deformation is performed to study the variation of consolidation settlement and the excess pore water pressure distribution in the central location and the part under centerline of the embankment. The results show that settlement develops gradually with the increasing period of soil consolidation. The excess pore water pressure of deep subgrade soils under embankment centerline rise due to the increased load. After each soil layer was filled, the excess pore water pressure increased in the first and was stable later along with the increase of soil depth. After the embankment soil was filled completely, excess pore pressure dissipated with time developing until the completion of consolidation.

scholarly journals EVALUASI SETTLEMENT MENGGUNAKAN SURCHARGE PRELOADING DENGAN PVD PADA PROYEK DI BANDUNG SELATAN

2020 ◽  
Vol 3 (3) ◽  
pp. 911
Author(s):  
Michael Christopher Yapriadi ◽  
Inda Sumarli ◽  
Ali Iskandar
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Improvement ◽  
Soil Layers ◽  
Excess Pore Water Pressure ◽  
Surcharge Preloading ◽  
Improvement Method ◽  
Degree Of Consolidation ◽  
Excess Pore

The development in Indonesia continues to grow. Hence, the feasible land for construction is drastically decreased. However, some projects must be constructed on that kind of land. One solution to solve this problem is by using a soil improvement. A project in Bandung Selatan chose to apply Surcharge Preloading with PVD soil improvement method. This project used a combination of 9,2 metres surcharge preload and a 28 metres depth PVD, with triangular formation and 1,2 metres spacing. The soil improvement was finished after 548 days. This analysis aims to evaluate the settlement from the soil improvement result, which is 1,297 metres. This analysis uses a finite difference method program. The excess pore water pressure from the analysis result is 0,229 T/m2 on the 548th day. Therefore, these soil layers have possibilities to settle again in future. The 90% degree of consolidation settlement for this soil layers is 2,31 metres, which will be reached on the 813,4th days. It is suspected that there are some mistakes either during the soil improvement designing or the soil improvement process. Pembangunan di Indonesia terus berkembang. Akibatnya jumlah tanah yang baik untuk proyek konstruksi semakin menipis. Kendati demikian, ada kalanya suatu proyek harus dilaksanakan di lokasi tersebut. Salah satu solusi yang dapat ditempuh adalah dengan melakukan perbaikan tanah. Sebuah proyek di Bandung Selatan melakukan perbaikan tanah dengan metode Surcharge Preloading dengan PVD. Proyek ini menggunakan kombinasi antara timbunan setinggi 9,2 meter dan PVD sedalam 28 meter, dengan formasi segitiga yang dipasang dengan jarak antar PVD 1,2 meter. Perbaikan tanah dilakukan selama 548 hari. Analisis ini bertujuan melakukan evaluasi terhadap kurang maksimalnya penurunan di lapangan yang hanya mencapai 1,297 meter. Analisis dilakukan dengan bantuan program beda hingga. Berdasarkan hasil analisis, besarnya excess pore water pressure pada hari ke-548 adalah 0,229 T/m,2, sehingga lapisan tanah tersebut masih memiliki potensi untuk mengalami penurunan. Adapun penurunan konsolidasi 90% yang dapat terjadi sebesar 2,31 meter pada hari ke-813,4. Diduga terdapat kesalahan baik dalam perhitungan perencanaan awal ataupun saat pelaksanaan di lapangan.

scholarly journals Analysis of Large-Strain Consolidation Behavior of Soil with High Water Content in Consideration of Self-Weight

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yupeng Cao ◽  
Jian Yang ◽  
Guizhong Xu ◽  
Jianwen Xu
Keyword(s):  
Pore Water ◽  
Void Ratio ◽  
Pore Water Pressure ◽  
Large Strain ◽  
Water Pressure ◽  
Average Degree ◽  
High Water Content ◽  
Excess Pore Water Pressure ◽  
Degree Of Consolidation ◽  
Excess Pore

Based on the axisymmetric large-strain consolidation (ALSC) model with the void ratio as the variable under equal strain condition, difference schemes of model’s equation, initial condition, and boundary condition were given. Taking phosphatic clay in Florida as a research object, the consolidation behaviors of soil with high water content by axisymmetric large-strain theory and one-dimensional large-strain theory were analyzed. The effect of different kinds of consolidation theories and self-weight stress on an average degree of consolidation was evaluated. The development of the void ratio and excess pore water pressure along the soil layer was clarified. The results show that the theoretical value of Terzaghi’s consolidation degree is always less than that of ALSC (Us, the average degree of consolidation defined by strain)-vertical drainage in the consolidation process. Terzaghi’s solution overestimates the dissipation rate of excess pore water pressure during the earlier consolidation period but underestimates it during the later consolidation period. The degree of consolidation calculated by Hansbo develops faster than ALSC (Up, the average degree of consolidation defined by stress)-radial drainage, but slower than ALSC (Us)-radial drainage. In the ALSC model, Us is always been faster than Up. The effect of self-weight on the consolidation degree of axisymmetric large-strain consolidation theory is relatively small (maximum error is less than 16%), while it can accelerate the consolidation rate of soil in one-dimensional large-strain consolidation theory largely. When only the vertical drainage occurs, the consolidation rate in the middle of the soil is obviously lagging the upper and lower parts, while the radial drainage can reduce the void ratio and the excess pore water pressure along the soil layer uniformly and more rapidly.

scholarly journals Analysis of settlement prediction due to preloading and vertical drain applications on runway construction

2020 ◽  
Vol 156 ◽  
pp. 02002
Author(s):  
Adriyati Meilani ◽  
Rifa’i Ahmad ◽  
Faris Fikri
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Layer ◽  
Soil Mass ◽  
Research Area ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Consolidation Settlement ◽  
Primary Consolidation

Consolidation settlement is a general geotechnical problem particularly found in the area where is composed of soft soil. It is caused by the discharge of pore water pressure induced by the increase of stress in the soil mass. Construction of runway above soft soil requires analysis for stability related to the reduction of consolidation settlement and the recovery. This study aims to analyze the settlement comprehensively using empirical methods of Prefabricated Vertical Drains (PVD) and preloading installation. Preloading is a technique by which consolidation of soil can be achieved to a substantial amount before the imposition of actual construction load. According to soil investigation, the characteristic of the soil layer is clay soil, which has the potential to consolidation settlement. The result of the settlement analysis of the taxiway in the research area is from 33 cm to 214 cm. It takes ten years for primary consolidation to reach a 90% degree of consolidation. However, in the Hansbo method of Prefabricated Vertical Drains (PVD) and preloading are applied, with triangular configurations in depth of 11 meters and duration for variation embankment spacing of 1 m is 79 days, 1.5 m is 202 days and 2 m is 390 days. The conclusion of efficient distance of PVD installation and preloading is spacing of 1 m with 79 days for primary consolidation.

One-dimensional consolidation under general time-dependent loading

2006 ◽  
Vol 43 (11) ◽  
pp. 1107-1116 ◽  
Author(s):  
Enrico Conte ◽  
Antonello Troncone
Keyword(s):  
Fourier Series ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Simple Calculation ◽  
Time Dependent ◽  
Coefficient Of Consolidation ◽  
One Dimensional ◽  
Practical Applications ◽  
Consolidation Time ◽  
General Time

This paper presents an analytical solution for the analysis of one-dimensional consolidation of saturated soil layers subjected to general time-dependent loading. A simple calculation procedure that makes use of the Fourier series is proposed for practical applications. Both single loads and cyclic loads can be considered by choosing a suitable period for the Fourier series. A number of comparisons with existing theoretical solutions are shown to assess the accuracy of the proposed procedure. Moreover, the experimental results from oedometer tests performed in the present study and from a well-documented case history concerning a large embankment constructed on compressible soils are analysed using this solution to evaluate the coefficient of consolidation of the soil.Key words: one-dimensional consolidation, time-dependent loading, excess pore-water pressure, theoretical solution, Fourier series.

scholarly journals Mechanical behaviour of calcareous waste under consolidated drained triaxial compression testing in saturated conditions

2019 ◽  
Vol 106 ◽  
pp. 01016
Author(s):  
Jakub Zięba
Keyword(s):  
Mechanical Behaviour ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Triaxial Compression ◽  
Soil Samples ◽  
Excess Pore Water Pressure ◽  
Stiffness Properties ◽  
Construction Purpose ◽  
Strength And Stiffness ◽  
Excess Pore

The article presents the mechanical behaviour of calcareous waste under consolidated and drained condition in Triaxial compression test (CD). The host material currently being considered for the construction purpose of several buildings in Poland. One of the location of calcareous waste is in Łagiewniki area (in Cracow) [1,2]. In this work, particular attention has been paid to the to ensure fully saturation for all the tested soil samples and avoid generation of unwanted excess pore water pressure during shearing stage. The saturation level of soil samples was estimated based on Skempton’s law (B>0.95). CD Triaxial test have been conducted in order to derive information on its strength and stiffness properties.

Stress–strain pattern–based criterion to assess cyclic shear resistance of soil from laboratory element tests

2016 ◽  
Vol 53 (9) ◽  
pp. 1460-1473 ◽  
Author(s):  
Dharma Wijewickreme ◽  
Achala Soysa
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Shear Stiffness ◽  
Large Strains ◽  
Fundamental Parameter ◽  
Stress Strain ◽  
Cyclic Shear ◽  
Excess Pore Water Pressure ◽  
Excess Pore

The cyclic shear response of soils is commonly examined using undrained (or constant-volume) laboratory element tests conducted using triaxial and direct simple shear (DSS) devices. The cyclic resistance ratio (CRR) from these tests is expressed in terms of the number of cycles of loading to reach unacceptable performance that is defined in terms of the attainment of a certain excess pore-water pressure and (or) strain level. While strain accumulation is generally commensurate with excess pore-water pressure, the definition of unacceptable performance in laboratory tests based purely on cyclic strain criteria is not robust. The shear stiffness is a more fundamental parameter in describing engineering performance than the excess pore-water pressure alone or shear strain alone; so far, no criterion has considered shear stiffness to determine CRR. Data from cyclic DSS tests indicate consistent differences inherent in the patterns between the stress–strain loops at initial and later stages of cyclic loading; instead of relatively “smooth” stress–strain loops in the initial parts of loading, nonsmooth changes in incremental stiffness showing “kinks” are notable in the stress–strain loops at large strains. The point of pattern change in a stress–strain loop provides a meaningful basis to determine the CRR (based on unacceptable performance) in cyclic shear tests.

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