Hailong Wang 교수

Over the past several years, the International Maritime Organization (IMO) has become increasingly concerned about the liquefaction of unsaturated solid bulk cargo (e.g. iron ore fines) during maritime transportation. This concern has arisen due to several accidents including the capsizing of vessels. In addition, although the resistance against liquefaction of ordinary unsaturated soils is higher than for saturated soils, possible key parameters governing the liquefaction resistance of unsatura

A testing procedure was proposed to study water movement in compacted bentonite and the development of swelling pressure (p s ) when compacted bentonite specimens were wetted. In this procedure, a multi-ring mold was introduced for p s measurements, after which the specimen was sliced for X-ray diffraction to find movement of water in the interlayer space of montmorillonite. Results revealed a relation between four phases of p s development and evolution of four states of interlayer water molecu

A swelling pressure cell is introduced to measure apparent swelling pressure (p s ) and basal spacing of montmorillonite (d 001 ) simultaneously for compacted bentonite during water absorption. Specimens with an initial dry density of up to 1·7 Mg/m 3 were prepared with initially oven-dried bentonite powder. Results show that the p s time history curve has four stages: a sharp increase to the peak swelling pressure (p p ); a drop to a valley swelling pressure (p v ); another increase to the init

This study starts from a question: how would initial water content (w i ) affect equilibrium swelling pressure (p eq ) of compacted bentonites in swelling pressure tests (p s tests)? However, discussions based on experiments involving a bentonite, Kunigel V1 (K_V1), are extended to the following issues: (a) the effect of w i on p eq ; (b) pore water density (ρ pw ); (c) the co-existence of crystalline and osmotic swelling; and (d) relation between p eq and compaction tests (p c tests). It is rev

Properties of the membrane filter recently introduced as an alternative to the ceramic disk are revealed through diffusion and hydraulic conductivity tests. It is shown that diffusion of air through the membrane filter is significantly affected by suction magnitude and that hydraulic conductivity of the membrane filter can easily be affected by the quality of water used in the test. The application of the membrane filter to the soil-water characteristic curve tests (SWCC tests) shows that simila

Abstract It is common to employ a traditional double cell system, of which an open-ended inner cell is installed in an ordinary triaxial apparatus, to measure the volume change of unsaturated specimens. In such a system, the total apparent volumetric strain of the specimen (εv) is deduced from the water level change in the inner cell, monitored by a differential pressure transducer (DPT) considering, meanwhile, the top cap intrusion into the inner cell recorded by a vertical displacement transdu

This paper reports the average pore water density (ρ wp ) measured on a Japanese bentonite, which was compacted to a dry density (ρ d ) range from 0·3 to 1·8 Mg/m 3 and saturated under a water pressure of 2·7 MPa. It was found that ρ wp monotonically increased from ∼1·0 Mg/m 3 at ρ d of 0·3 Mg/m 3 to ∼1·23 Mg/m 3 at ρ d of 1·8 Mg/m 3 . A review of the available literature revealed that the methodology of accurately measuring ρ wp in a full range of water content (w) is not available. An upper bo

With the interests to see specimen thickness (hsp) effect on apparent swelling pressure (ps) of compacted bentonite and capture characteristics of ps development during wetting bentonite specimens (ps evolution, hereafter), a series of tests to measure ps of compacted bentonite specimens with a dry density (ρd) range of 0.99–1.76 Mg/m3 and a specimen thickness (hsp) range of 2–10 mm were conducted. Test results suggest: (1) ps evolution generally has common characteristics with four feature poin

Concerning the static liquefaction properties of an industrial cargo, i.e., iron ore fines (IOF), undrained monotonic behaviors of a type of IOF are revealed through conducting triaxial compression tests. It is found that IOF exhibit some similar behaviors as those of common sandy soils, while some very unusual behaviors are also observed. All IOF specimens with compaction degree of 84%–95% and confining pressure of 50–200 kPa exhibit dilative behavior from the beginning of axial loading until t

Accidents and life loss caused serious concern on the liquefaction problem of some solid bulk cargoes such as iron ore fines during transportation at sea. To understand the liquefaction property of a type of iron ore fines, a series of tests, e.g. SEM observation, monotonic loading triaxial test, cyclic loading triaxial test etc. were conducted. Test results show that this unusual material possesses some special properties, for instance, much higher specific gravity Gs (average Gs=4.444) as comp

Abstract The details of a multifunctional triaxial system developed for unsaturated soils over the past ten years at The University of Tokyo are described. This study first briefly reviewed three functions of the triaxial system developed for the undrained cyclic loading test to evaluate liquefaction properties of unsaturated soils. In the triaxial system, accurate measurement of volumetric deformation was achieved with a linkage double cell system, application of the membrane filter technique g

Evaluations of water retention characteristics of typical iron ore fines (IOF) were presented, which was part of experimental works for the estimation of liquefaction potential of IOF heaps. The water retention tests were conducted in a suction range from 0.1 to 10 6 kPa on two IOFs and two artificial soils with various testing techniques. It is observed that water retention characteristic curves of one IOF (IOF-B) converge in terms of the relationship between suction (S) and water content (w) r

Bentonite is considered a barrier material in the geological disposal of high-level radioactive waste. Depending on the construction method, it is necessary to know what the behavior of the bentonite barrier will be in the wetting process during the absorption of underground water under different boundary conditions. In this study, water and soil particle movement during the wetting process of a compacted bentonite under constrained and free swelling conditions was studied experimentally and num

A series of undrained cyclic loading tests of three types of saturated and unsaturated soils were conducted on a triaxial apparatus. To overcome the difficulties of this type of test, cell pressure control system to maintain constant p, membrane filter technique to measure pore water pressure and double cell system to measure volumetric strain (ϵv) were introduced to the apparatus. Test results shown that the cell pressure control system reduced more than 60% variation of p which would

Concerning on the liquefaction behavior of a type of bulk cargoes, iron ore fines (IOF), during maritime time transportation, systematic experimental and numerical programs were conducted. In this study, as an important parameter for seepage analysis, permeability of saturated and unsaturated typical IOF were evaluated in a triaxial system. As a comparison, similar tests were also conducted on a widely used laboratory material, Toyoura sand. The tests were conducted very carefully considering ef