Use of the static penetration test in frozen soils

1976 ◽  
Vol 13 (2) ◽  
pp. 95-110 ◽  
Author(s):  
B. Ladanyi
Keyword(s):  
Penetration Rate ◽  
Triaxial Compression ◽  
Field Investigation ◽  
Frozen Soil ◽  
Time To Failure ◽  
Compression Tests ◽  
Penetration Test ◽  
Frozen Soils ◽  
Static Penetration ◽  
Investigation Methods

Within the scope of a study on the use in frozen soils of some geotechnical field investigation methods, a series of deep, static and quasi-static, penetration tests was carried out in July 1974 at a permafrost site near Thompson, Manitoba. The field study included stress – and penetration rate – controlled tests, performed with an electric penetrometer, as well as several short-term and stage-loaded pressuremeter tests. The study shows that a static penetration test can furnish valuable information on the time-dependent strength of frozen soil, provided the test is conducted either with a very accurate control of the penetration rate, or as a stage-loaded test. It is considered that a comparison of frozen soil strengths deduced from such a test, with those determined by pressuremeter tests or triaxial compression tests, can only be made at comparable strain rates. An attempt was, therefore, made in the paper to find a relationship between the penetration rate and an equivalent time to failure for the soil surrounding the penetrometer tip, which enabled this comparison to be carried out.

scholarly journals TRIAXIAL COMPRESSION TESTING OF FROZEN SOILS FOR THE DETERMINATION OF RHEOLOGICAL PARAMETERS

2018 ◽  
pp. 18-24
Author(s):  
V. A. Ageenko ◽  
M. N. Tavostin ◽  
I. S. Vakulenko
Keyword(s):  
Triaxial Compression ◽  
Test Procedure ◽  
Estimation Method ◽  
Mechanical Deformation ◽  
Frozen Soil ◽  
Compression Testing ◽  
Test Material ◽  
Rheological Parameters ◽  
Compression Tests ◽  
Frozen Soils

Detailed investigation of mechanical, deformation and rheological properties of frozen soils is an actual issue, as they are basis of civil- engineering survey for underground constructions in permafrost  holding more than 50% of the territory of Russia. The majority of  modern software packages which calculate structures stability  considering stress state of soils massive, demand knowledge of  mechanical and rheological parameters defined by triaxial  compression tests. The current article presents: estimation method  of frozen soils rheological parameters by triaxial compression  testing; required equipment and the research results. The samples  of frozen soil 10 – 50 m depth from Kharasavey gas field were used  as test material. Mostly they are presented by loam, clay and sand.  The experiments were run at the range of temperature from −3°C to −6°C.. Triaxial compression testing was provided by the laboratory  equipment which allows to run experiments in the mode of  automatic load, maintenance and deformation processes  registration. Test procedure of rheological parameters identification  under conditions of long-term triaxial compression considered  incremental load Stage duration was equal to 24 hours. The  experiments were run until th specimen’s failure. As a result of the  testing, mechanical, deformation and rheological parameters for  frozen soils are defined at temperatures −3°C  −6°C. The achieved results can be interpreted in different models (Mohr-Coulomb,  Drucker-Prager, Tresca etc.). The described experiments were carried out at LLC Gazprom Geotechnology for the design of underground drill cutting s storages in permafrost.

scholarly journals A Nonlinear Strength Criterion for Frozen Sulfate Saline Silty Clay with Different Salt Contents

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yanhu Zhao ◽  
Yuanming Lai ◽  
Jing Zhang ◽  
Chong Wang
Keyword(s):  
Triaxial Compression ◽  
Strength Criterion ◽  
Experimental Results ◽  
Saline Soils ◽  
Silty Clay ◽  
Compression Tests ◽  
Frozen Soils ◽  
Conventional Triaxial Compression ◽  
Confining Pressures ◽  
Pressure Melting

It has been proven that the mechanical properties of frozen saline soils are different from frozen soils and unfrozen saline soils. In this paper, in order to study the effects of the salt contents on the strength characteristics of frozen soils, a series of conventional triaxial compression tests are carried out for frozen saline silty clay with Na2SO4 contents 0.0, 0.5, 1.5, and 2.5% under confining pressures from 0 MPa to 18 MPa at −6°C, respectively. The experimental results show that the strength of frozen saline silty clay presents obvious nonlinearity, the strength of frozen saline silty clay increases with increasing confining pressures at first, but with a further increase in confining pressures, the strength decreases because of pressure melting and crushing phenomena under high confining pressures, and salt contents have an important influence on strength of frozen saline silty clay. A strength criterion is proposed on the basis of the experimental results. The strength criterion could well reflect the nonlinear strength characteristic of frozen saline silty clay and the influence of salt contents on frozen saline silty clay.

Use of the static penetration test method to investigate the properties of frozen soils

1991 ◽  
Vol 28 (3) ◽  
pp. 121-126 ◽  
Author(s):  
O. N. Isaev ◽  
V. V. Shvarev ◽  
S. M. Tikhomirov ◽  
A. V. Sadovskii ◽  
A. V. Konstantinov
Keyword(s):  
Test Method ◽  
Penetration Test ◽  
Frozen Soils ◽  
Static Penetration

A Simple Unconsolidated Undrained Triaxial Compression Test Emulator

2015 ◽  
Vol 771 ◽  
pp. 104-107
Author(s):  
Riska Ekawita ◽  
Hasbullah Nawir ◽  
Suprijadi ◽  
Khairurrijal
Keyword(s):  
Triaxial Compression ◽  
Measurement Data ◽  
Radial Strain ◽  
Compression Tests ◽  
Viscous Effects ◽  
Axial Pressure ◽  
Strain Stress ◽  
The University ◽  
And Storage ◽  
Triaxial Compression Tests

An unconsolidated undrained (UU) test is one type of triaxial compression tests based on the nature of loading and drainage conditions. In order to imitate the UU triaxial compression tests, a UU triaxial emulator with a graphical user interface (GUI) was developed. It has 5 deformation sensors (4 radial deformations and one vertical deformation) and one axial pressure sensor. In addition, other inputs of the emulator are the cell pressure, the height of sample, and the diameter of sample, which are provided by the user. The emulator also facilitates the analysis and storage of measurement data. Deformation data fed to the emulator were obtained from real measurements [H. Nawir, Viscous effects on yielding characteristics of sand in triaxial compression, Dissertation, Civil Eng. Dept., The University of Tokyo, 2002]. Using the measurement data, the stress vs radial strain, stress vs vertical strain, and Mohr-Coulomb circle curves were obtained and displayed by the emulator.

scholarly journals Effects of preferential flow on snowmelt partitioning and groundwater recharge in frozen soils

2019 ◽  
Vol 23 (12) ◽  
pp. 5017-5031 ◽  
Author(s):  
Aaron A. Mohammed ◽  
Igor Pavlovskii ◽  
Edwin E. Cey ◽  
Masaki Hayashi
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Preferential Flow ◽  
Frozen Soil ◽  
Time Lags ◽  
Runoff Generation ◽  
Frozen Ground ◽  
Soil Matrix ◽  
Frozen Soils ◽  
Flow Through

Abstract. Snowmelt is a major source of groundwater recharge in cold regions. Throughout many landscapes snowmelt occurs when the ground is still frozen; thus frozen soil processes play an important role in snowmelt routing, and, by extension, the timing and magnitude of recharge. This study investigated the vadose zone dynamics governing snowmelt infiltration and groundwater recharge at three grassland sites in the Canadian Prairies over the winter and spring of 2017. The region is characterized by numerous topographic depressions where the ponding of snowmelt runoff results in focused infiltration and recharge. Water balance estimates showed infiltration was the dominant sink (35 %–85 %) of snowmelt under uplands (i.e. areas outside of depressions), even when the ground was frozen, with soil moisture responses indicating flow through the frozen layer. The refreezing of infiltrated meltwater during winter melt events enhanced runoff generation in subsequent melt events. At one site, time lags of up to 3 d between snow cover depletion on uplands and ponding in depressions demonstrated the role of a shallow subsurface transmission pathway or interflow through frozen soil in routing snowmelt from uplands to depressions. At all sites, depression-focused infiltration and recharge began before complete ground thaw and a significant portion (45 %–100 %) occurred while the ground was partially frozen. Relatively rapid infiltration rates and non-sequential soil moisture and groundwater responses, observed prior to ground thaw, indicated preferential flow through frozen soils. The preferential flow dynamics are attributed to macropore networks within the grassland soils, which allow infiltrated meltwater to bypass portions of the frozen soil matrix and facilitate both the lateral transport of meltwater between topographic positions and groundwater recharge through frozen ground. Both of these flow paths may facilitate preferential mass transport to groundwater.

Strength envelope of granular soil stabilized by multi-axial geogrid in large triaxial tests

2020 ◽  
Vol 57 (3) ◽  
pp. 448-452 ◽  
Author(s):  
A.S. Lees ◽  
J. Clausen
Keyword(s):  
Triaxial Compression ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Failure Envelope ◽  
Element Analysis ◽  
Linear Elastic ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Triaxial Compression Tests ◽  
Properties Of Soil

Conventional methods of characterizing the mechanical properties of soil and geogrid separately are not suited to multi-axial stabilizing geogrid that depends critically on the interaction between soil particles and geogrid. This has been overcome by testing the soil and geogrid product together as one composite material in large specimen triaxial compression tests and fitting a nonlinear failure envelope to the peak failure states. As such, the performance of stabilizing, multi-axial geogrid can be characterized in a measurable way. The failure envelope was adopted in a linear elastic – perfectly plastic constitutive model and implemented into finite element analysis, incorporating a linear variation of enhanced strength with distance from the geogrid plane. This was shown to produce reasonably accurate simulations of triaxial compression tests of both stabilized and nonstabilized specimens at all the confining stresses tested with one set of input parameters for the failure envelope and its variation with distance from the geogrid plane.

scholarly journals Mechanical behavior of frozen soil improved with sulphoaluminate cement and its microscopic mechanism

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhenhua Yin ◽  
Hu Zhang ◽  
Jianming Zhang ◽  
Mingtang Chai
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Soil Improvement ◽  
Particle Size Analysis ◽  
Frozen Soil ◽  
Size Analysis ◽  
Permafrost Soil ◽  
Compression Tests ◽  
Microscopic Mechanism ◽  
Sulphoaluminate Cement

Abstract The foundation of constructions built in the permafrost areas undergo considerable creeping or thawing deformation because of the underlying ice-rich permafrost. Soil improvement may be of advantage in treating ice-rich permafrost at shallow depth. Sulphoaluminate cement was a potential material to improve frozen soil. Simultaneously, two other cements, ordinary Portland cement and Magnesium phosphate cement were selected as the comparison. The mechanical behavior of modified frozen soil was studied with thaw compression tests and unconfined compression strength tests. Meanwhile, the microscopic mechanism was explored by field emission scanning electron microscopy, particle size analysis and X-ray diffractometry. The results showed Sulphoaluminate cement was useful in reducing the thaw compression deformation and in enhancing the strength of the frozen soil. The improvement of the mechanical behavior depended mainly on two aspects: the formation of structural mineral crystals and the agglomeration of soil particles. The two main factors contributed to the improvement of mechanical properties simultaneously. The thicker AFt crystals result in a higher strength and AFt plays an important role in improving the mechanical properties of frozen soils.The study verified that Sulphoaluminate cement was an excellent stabilizer to improve ice-rich frozen soils.

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