Effects of soil parameters on pore-pressure-rise and liquefaction prediction

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).

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Sensitivity Analysis of Geomechanical Constraints in CO2 Storage to Screen Potential Sites in Deep Saline Aquifers

Frontiers in Climate ◽

10.3389/fclim.2021.720959 ◽

2021 ◽

Vol 3 ◽

Author(s):

Yashvardhan Verma ◽

Vikram Vishal ◽

P. G. Ranjith

Keyword(s):

Sensitivity Analysis ◽

Pore Pressure ◽

Co2 Storage ◽

Pressure Rise ◽

Injection Rate ◽

Early Years ◽

Rock Properties ◽

Deep Aquifers ◽

Plume Migration ◽

Storage Potential

In order to tackle the exponential rise in global CO2 emissions, the Intergovernmental Panel on Climate Change (IPCC) proposed a carbon budget of 2,900 Gt to limit the rise in global temperature levels to 2°C above the pre-industrial level. Apart from curbing our emissions, carbon sequestration can play a significant role in meeting these ambitious goals. More than 500 Gt of CO2 will need to be stored underground by the end of this century to make a meaningful impact. Global capacity for CO2 storage far exceeds this requirement, the majority of which resides in unexplored deep aquifers. To identify potential storage sites and quantify their storage capacities, prospective aquifers or reservoirs need to be screened based on properties that affect the retention of CO2 in porous rocks. Apart from the total volume of a reservoir, the storage potential is largely constrained by an increase in pore pressure during the early years of injection and by migration of the CO2 plume in the long term. The reservoir properties affect both the pressure buildup and the plume front below the caprock. However, not many studies have quantified these effects. The current analysis computes the effect of rock properties (porosity, permeability, permeability anisotropy, pore compressibility, and formation water salinity) and injection rate on both these parameters by simulating CO2 injection at the bottom of a 2D mesh grid with hydrostatic boundary conditions. The study found that the most significant property in the sensitivity analysis was permeability. Porosity too affected the CO2 plume migration substantially, with higher porosities considerably delaying horizontal and vertical migration. Injection rate impacted both the pressure rise and plume migration consistently. Thus, in screening potential storage sites, we can infer that permeability is the dominant criterion when the pore pressure is closer to the minimum principal stress in the rocks, due to which injection rate needs to be managed with greater caution. Porosity is more significant when the lateral extents of the reservoir limit the storage potential.

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A Theoretical and Experimental Investigation of Mildly Nonlinear Consolidation Behavior in Saturated Soil

Canadian Geotechnical Journal ◽

10.1139/t71-019 ◽

1971 ◽

Vol 8 (2) ◽

pp. 182-216 ◽

Cited By ~ 2

Author(s):

T. J. Poskitt ◽

R. O. Birdsall

Keyword(s):

Pore Pressure ◽

Large Strain ◽

Saturated Soil ◽

Soil Parameters ◽

Viscous Effects ◽

Variable Permeability ◽

Linear Behavior ◽

Soil Skeleton ◽

The One ◽

Physical Laws

A theory is given which enables variable permeability and compressibility, large strain, and non-Newtonian viscous effects in the soil skeleton to be considered in the one-dimensional consolidation of saturated soil. The first three of these are fairly well understood phenomena and their influence on field behavior is predictable. The last, however, is much more open to interpretation and has been included to cover laboratory testing of thin samples where viscous effects are often known to be important. The rheological model used for the soil skeleton is of the same general form as that used by Gibson and Lo in their investigation of linear behavior in clays. However, in the present case nonlinear physical laws of a form known to fit the experimental data more closely have been used. This makes the governing equations nonlinear and they are correspondingly more difficult to solve. The principal theoretical results for settlement and pore pressure are given in a form convenient for practical use and a procedure is given whereby the basic soil parameters can be determined from a laboratory settlement curve. By using the parameters so obtained the theoretical midplane pore pressure can be computed and when compared with the experimental curve this gives a stringent test of the adequacy of the theory. Experimental results for three different clays are given, and the theory shows encouraging agreement with these.

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Experimental Study for Wave-Induced Oscillatory Pore Pressures in a Sandy Seabed

Volume 3: Offshore Geotechnics ◽

10.1115/omae2014-24479 ◽

2014 ◽

Author(s):

Bo Liu ◽

Dong-Sheng Jeng ◽

Guanlin Ye

Keyword(s):

Experimental Study ◽

Pore Pressure ◽

Vertical Cylinder ◽

Soil Conditions ◽

Soil Parameters ◽

Pore Pressures ◽

Sandy Deposit ◽

Dimensional Facility ◽

Set Up ◽

Wave Induced

In this paper, an experimental study for wave-induced pore pressures in marine sediments was reported. In the experiment, a one-dimensional facility was set up with a vertical cylinder and a 1.8 m thick sandy deposit and 0.2 m thick water above the deposit. Unlike the previous experiments [1], additional static water pressures were added on the harmonic dynamic wave pressure and more pore pressure gauges were buried in the deposit, which allowed us to simulate the case with larger water depth and better describe the distribution of pore pressure trend. A series of experiments with 3000 cycles in each test were conducted under numerous different wave and soil conditions, which allowed us to examine the influence of wave and soil parameters on the wave-induced pore pressures as well as liquefaction. The experimental results show the significant influence of liquefaction on sandy seabed in shallow water. Furthermore, some new experimental phenomenon was observed. The depth of sandy deposit was usually considered to be unchanged in theoretical calculation, while the depth of which was indeed changed periodic with wave loading, which was observed and recorded in the experiments.

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