On Hook Formulas for Cylindric Skew Diagrams

We present a conjectual hook formula concerning the number of the standard tableaux on "cylindric" skew diagrams. Our formula can be seen as an extension of Naruse's hook formula for skew diagrams. Moreover, we prove our conjecture in some special cases

Analysis of Fatal Accidents Caused by Trench Failure

The purpose of this paper is to clarify the failure mechanism and how workers died due to trench failures with close examination of the situations surrounding these accidents. We carried out a statistical analysis of various factors obtained from fatal accident data which were reported by the Labour Standard Office to the Ministry of Labour. This examination revealed some important characteristics of fatal accidents due to trench failures

Case History of Labor Accident Due to Slope Failure During Slope Excavation and Its Countermeasure Work

About 15 to 20 workers die annually in labor accidents attributed to slope failure or rock fall during slope excavations in Japan. In this paper, a case history of slope failure occurred during the reconstruction of retaining wall is presented. The geotechnical centrifuge model tests are conducted to investigate the mechanism of slope failure. This paper focuses on the influence of wall stiffness and embedded depths of sheet piles or pipes on the prevention of slope failure. Based on the centrifuge test, it was found that the simple temporary wall used during the trench excavation in this case history could not protect to worker from the slope failure

Case History and Numerical Analysis of Trench Collapse in Japan

This paper presents a case history of trench collapse occurred during trench excavation in soft ground. The development of settlement and horizontal displacement, the generation of pore water pressure during the construction and mechanism of trench collapse are investigated by means of centrifuge modeling and numerical analysis. It is found that the combination of centrifuge modeling and in-flight sand hopper can provide dramatic result for simulation of the trench collapse. Based on the results, it is verified that the occurrence of trench collapse is mainly caused by the excessive surcharge load of excavated material stockpiled on top of the trench

Lessons Learned from Slope and Trench Failures in Japan

This paper presents case histories of slope and trench failure accidents in Japan during the period of 1989 to 2001 based on the database from construction industrial labor accident reports. The major risk factors of the failures are identified by considering the location of slope and trench failures, types of construction, slope and trench geometries, scale of slope failure, time of occurrence and characteristics of worker involved in the failures. It was found that it is necessary to improve the safety standards and provide more safety education and training especially in the small construction projects to prevent the slope and trench excavations in future

Centrifuge Model Test on the Stability of a Clayey Ground Improved by Deep Mixing Method With a Low Improvement Ratio

In this study, centrifuge model tests and numerical analysis were carried out to investigate effects of improvement by deep mixing method (DMM). Model grounds used in model tests were (1) unimproved ground (easel), (2) improved ground with vertical soil columns under toe of slopes (case2), (3) improved ground with vertical soil columns under shoulder of slopes (case3), (4) improved ground with inclined soil columns under toe of slopes (case4), and (5) improved ground with inclined soil columns under shoulder of slopes (case5). The improvement ratio was about 10% for all test cases except easel. The embankment was constructed by sand dropped from the sand hopper under 56g centrifugal field. Following conclusions were obtained from the model tests and the numerical analysis. 1) The deformation of ground was considerably controlled in spite of adopting the low improvement ratio of 10%. 2) For preventing the failure or the large deformation of ground, ground improvement just below the shoulder of the slope was more effective than that bellow toe of the slope. 3) Numerical analysis by means of FEM could be utilized to simulate the tendency of deformation behaviors of soft grounds

Modified line-assisted complete closure of the defect after gastric endoscopic full-thickness resection: a pilot study in porcine models

Background and study aims Closure after endoscopic full-thickness resection (EFTR) is challenging. We previously developed a simple endoscopic closure method: line-assisted complete closure (LACC). We performed a pilot study using porcine models to evaluate the feasibility of modified LACC after gastric EFTR. Patients and methods Six live pigs were included. EFTR (greater curvature of the gastric antrum [n = 3] and anterior wall of the gastric body [n = 3]) was performed under general anesthesia and the defect after EFTR was closed by modified LACC. The pigs were observed until postoperative day 4 (Day 4). The closure site was endoscopically evaluated and the presence or absence of peritonitis and fluid leakage was evaluated. The outcomes were the success rate of modified LACC on the day of the procedure, maintenance of defect closure, presence of peritonitis or leakage, and clinical course. Results Once complete closure was successfully achieved in all cases, maintenance of closure on Day 4 was not achieved. However, there was neither peritonitis nor fluid leakage. The defect was completely covered by surrounding tissues on Day 4 and the clinical course was good in all cases. Conclusions The feasibility of modified LACC after gastric EFTR was demonstrated in porcine models. Further improvement is needed to maintain defect closure

A Case History of the Collapse Accident of a Temporary Earth Support Structure

This paper presents a case study on the collapse accident of a temporary earth support structure. The examination of the design plans and investigations of the construction site where the accident occurred bas been carried out to throw light on the accident situations. Some causes of the accident occurrence which have been derived from these examinations and countermeasures for prevention of these types of accidents are discussed