A Field Test Study on Instrumented Soil Nail Installed in Cut Slope

Soil nailing is a technique routinely used in Hong Kong whereby closely spaced steel bars are installed into a slope so that its stability conditions can be improved. A full-scale field test has been carried out by The Department of Civil Engineering of The University of Hong Kong to study the development of passive load along the full length of soil nails when subjected to induced rise in groundwater table. The cut slope was formed to a very steep angle of 55° and 10 m high in completely decomposed volcanic material. Grouted curtain was also formed behind, at the bottom and on both ends of the slope in order to form an impermeable barrier that would allow groundwater table to increase artificially by injecting water into slotted PVC pipes. Nine number of soil nails (in regular 2 m c/c spacing of 3 rows and 3 columns) of 6 m long high yield steel bar were installed at 15° from horizontal into the formed cut slope. Instrumentation included strain gauges along the nails, inclinometers, piezometers, and settlement prisms. This paper describes the method of construction and the load developed along the soil nails when the groundwater table was raised to the ground surface. It was found that the measured passive load along the soil nail was smaller than the commonly assumed design parameters, an indication that substantial savings can be achieved if mobilization of shearing resistance along the full length of the soil nail was considered in routine design. Finite element analysis has also been carried out to compare the measured load with the simulated load and the stability factor is compared with the factor of safety at each stage of loading

Slope Stability Evaluation for an Existing Steep Cut in Weathered Volcanics, Hong Kong

This case study concerns an investigation of a major existing soil slope. It is a 60m (197 ft) high cutting slope, at 40 degrees to 60 degrees to the horizontal, exhibiting a considerably greater degree of stability than was obtained by a series of geotechnical investigations and analyses. The common practice of correlation between widely spaced borings is shown to be inappropriate at this site because of the highly variable ground conditions. Rather, the comprehensive geological comprehensive engineering investigation carried out has enabled a detailed appreciation of the distribution and nature of weathered materials at the site. Transitional materials with soil-like appearance and weak rock properties have been identified. Based on this information, slope stability evaluation was carried out with more realistic results and with greater confidence

A note on the realignment criterion

For a quantum state in a bipartite system represented as a density matrix, researchers used the realignment matrix and functions on its singular values to study the separability of the quantum state. We obtain bounds for elementary symmetric functions of singular values of realignment matrices. This answers some open problems proposed by Lupo, Aniello, and Scardicchio. As a consequence, we show that the proposed scheme by these authors for testing separability would not work if the two subsystems of the bipartite system have the same dimension.Comment: 11 pages, to appear in Journal of Physics A: Mathematical and Theoretica

A Field Test Study on under Water Vacuum Preloading Method

Vacuum preloading technique incorporating prefabricated vertical drains is one of the most widely used ground improvement methods in the world for improving the engineering properties of soft clays. Although many successful on-shore cases on application of the technique have been reported, the effectiveness of applying the technique under water has not yet been investigated. Moreover, many technical and operation factors, that are playing important roles in vacuum consolidation, are also not yet fully understood. To study the feasibility of under water vacuum preloading, a large-scale field test was conducted. A 50 m by 50 m geo-membrane was laid under water in an 80 m wide by 100 m long pond. The geo-membrane was custom made with drainage outlet pipes to release the trapped air bubbles during the placement under water. Prefabricated vertical drains were installed on an equilateral triangular grid at a spacing of 1.2 m to a depth of 7 m. Internal drainage pipes were provided in the sand cushion layers to provide a passage for the prefabricated vertical drains with the external vacuum pumps. Instruments such as piezometers, vacuum sensors, inclinometers, settlement plates and extensometers were installed to monitor the performance of the system. An automatic and remote wireless monitoring system was installed for data collection because of difficult access. Vane shear tests and cone penetration tests were conducted before and after vacuum preloading to determine the effectiveness of the operation. This paper documents the constructions of the field test and reports the major observations from the monitored readings. The operation has demonstrated that under water vacuum preloading is feasible and that with proper design and construction procedure, a very tight seal can be provided by the geo-membrane separating the water and the underlying prefabricated vertical drains through out the test. The monitored results demonstrate that the stiffness and strength of the soft clay can be improved effectively

RELBET 4.0 user's guide

This manual describes the operation and use of RELBET 4.0 implemented on the Hewlett Packard model 9000. The RELBET System is an integrated collection of computer programs which support the analysis and post-flight reconstruction of vehicle to vehicle relative trajectories of two on-orbit free-flying vehicles: the Space Shuttle Orbiter and some other free-flyer. The manual serves both as a reference and as a training guide. Appendices provide experienced users with details and full explanations of program usage. The body of the manual introduces new users to the system by leading them through a step by step example of a typical production. This should equip the new user both to execute a typical production process and to understand the most significant variables in that process

Fine structure splittings of excited P and D states in charmonium

It is shown that the fine structure splittings of the $2 ^3P_J$ and $3 ^3P_J$ excited states in charmonium are as large as those of the $1^3P_J$ state if the same $\alpha_s(\mu)\approx 0.36$ is used. The predicted mass $M(2 ^3P_0)=3.84$ GeV appears to be 120 MeV lower that the center of gravity of the $2 ^3P_J$ multiplet and lies below the $D\bar D^*$ threshold. Our value of $M(2 ^3P_0)$ is approximately 80 MeV lower than that from the paper by Godfrey and Isgur while the differences in the other masses are \la 20 MeV. Relativistic kinematics plays an important role in our analysis.Comment: 12 page

Nonet Symmetry and Two-Body Decays of Charmed Mesons

The decay of charmed mesons into pseudoscalar (P) and vector (V) mesons is studied in the context of nonet symmetry. We have found that it is badly broken in the PP channels and in the P sector of the PV channels as expected from the non-ideal mixing of the \eta and the \eta'. In the VV channels, it is also found that nonet symmetry does not describe the data well. We have found that this discrepancy cannot be attributed entirely to SU(3) breaking at the usual level of 20--30%. At least one, or both, of nonet and SU(3) symmetry must be very badly broken. The possibility of resolving the problem in the future is also discussed.Comment: 9 pages, UTAPHY-HEP-

Asymptotic analysis of a secondary bifurcation of the one-dimensional Ginzburg-Landau equations of superconductivity

The bifurcation of asymmetric superconducting solutions from the normal solution is considered for the one-dimensional Ginzburg--Landau equations by the methods of formal asymptotics. The behavior of the bifurcating branch depends on the parameters d, the size of the superconducting slab, and $\kappa$, the Ginzburg--Landau parameter. The secondary bifurcation in which the asymmetric solution branches reconnect with the symmetric solution branch is studied for values of $(\kappa,d)$ for which it is close to the primary bifurcation from the normal state. These values of $(\kappa,d)$ form a curve in the $\kappa d$-plane, which is determined. At one point on this curve, called the quintuple point, the primary bifurcations switch from being subcritical to supercritical, requiring a separate analysis. The results answer some of the conjectures of [A. Aftalion and W. C. Troy, Phys. D, 132 (1999), pp. 214--232]

Implications of New Gallex Results for the MSW Solution of the Solar Neutrino Problem

We compare the implications for 7Be and pp neutrinos of the two MSW fits to the new GALLEX solar neutrino measurements . Small mixing angle solutions tend to suppress the former as electron-neutrinos, but not the latter, and large angle solutions tend to reduce both by about a factor of 2. The consequences for BOREXINO and similar solar neutrino--electron scattering experiments are discussed.Comment: 7 pages (plus 3 figures available upon request) UTAPHY-HEP-