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1.
World J Pediatr Surg ; 5(2): e000350, 2022.
Article in English | MEDLINE | ID: mdl-36474514

ABSTRACT

Objective: The Japan Coma Scale (JCS) is widely used in clinical practice to evaluate levels of consciousness in Japan. There have been several studies on the usefulness of JCS in adults. However, its usefulness in evaluating children has not been reported. Therefore, this study aimed to assess the usefulness of the JCS for the prediction of mortality in children. Methods: This is a multicenter cohort study which used data from a national trauma registry (Japan Trauma Data Bank). This study included patients under 16 years of age who were treated between 2004 and 2015.The primary outcome measure was in-hospital mortality. Two models were used to examine each item of the Glasgow Coma Scale (GCS) and the JCS. Model A included the discrete levels of each index. In model B, data regarding age, sex, vital signs on arrival to hospital, the Injury Severity Score, and blunt trauma were added to each index. The effectivity of the JCS score was then evaluated using the area under the curve (AUC) for discrimination, a calibration plot, and the Hosmer-Lemeshow test for calibration. Results: A total of 9045 patients were identified. The AUCs of the GCS and JCS were 0.929 (95% confidence interval (CI) 0.904 to 0.954) and 0.930 (95% CI 0.906 to 0.954) in model A and 0.975 (95% CI 0.963 to 0.987) and 0.974 (95% CI 0.963 to 0.985) in model B, respectively. The results of the Hosmer-Lemeshow test were 0.00 (p=1.00) and 0.00 (p=1.00) in model A and 4.14 (p=0.84) and 8.55 (p=0.38) in model B for the GCS and JCS, respectively. Conclusions: We demonstrated that the JCS is as valid as the GCS for predicting mortality. The findings of this study indicate that the JCS is a useful and relevant tool for pediatric trauma care and future research.

2.
Asian J Neurosurg ; 17(4): 638-641, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36570747

ABSTRACT

Rapid advances in emergent mechanical thrombectomy have resulted in a higher occurrence of arterial perforations during neurointerventions. Here, we report a case of internal carotid artery (ICA) perforation during mechanical thrombectomy in a 78-year-old man with a left middle cerebral artery occlusion. The ICA was perforated by a microcatheter during thrombectomy, forming a direct carotid-cavernous fistula. A two-stage drainer occlusion was conducted because of cortical venous reflex aggravation and ocular symptoms. Here, we report the perforation details and treatment, adding to evidence that ICA perforation with the microcatheter body is a concern during mechanical thrombectomy.

3.
Neurol Med Chir (Tokyo) ; 61(9): 521-527, 2021 Sep 15.
Article in English | MEDLINE | ID: mdl-34121049

ABSTRACT

Various approaches have been tried for acute ischemic stroke (AIS) treatment to shorten the time from onset to recanalization. MRI positioning scanning (PS), which must be taken before any MRI sequences, was examined whether it can detect cerebral large vessel occlusion. A total of 68 consecutive patients with AIS who underwent MRI and were treated with intravenous recombinant tissue plasminogen activator or mechanical thrombectomy at our hospital were retrospectively included in this study. Occluded vessels were identified on the axial or coronal views of PS images, and these images were compared with 3D time-of-flight MRA and digital subtraction angiogram. The sensitivities, positive predictive values (PPVs), and negative predictive values (NPVs) for internal carotid artery (ICA), the proximal M1, distal M1, and M2 segment of the middle cerebral artery occlusion were assessed, and the number of PS slices was assessed. The sensitivities of the axial slices for ICA, proximal M1, distal M1, and M2 occlusion were 62%, 21%, 35%, and 86%, respectively. The PPVs of the axial slices for ICA, proximal M1, distal M1, and M2 occlusion were 81%, 88%, 100%, and 97%, respectively, and the NPVs of the axial slices for ICA, proximal M1, distal M1, and M2 occlusion were 94%, 90%, 86%, and 100%, respectively. The detection rate for the ICA was significantly higher with three axial slices (91%) than with two slices (47%) (p <0.01). MRI PS is warranted to be referred to detect large cerebral vessel occlusion.


Subject(s)
Brain Ischemia , Ischemic Stroke , Stroke , Brain Ischemia/diagnostic imaging , Humans , Infarction, Middle Cerebral Artery/diagnostic imaging , Magnetic Resonance Imaging , Retrospective Studies , Stroke/diagnostic imaging , Thrombectomy , Tissue Plasminogen Activator , Treatment Outcome
5.
Interv Neuroradiol ; 27(5): 672-676, 2021 Oct.
Article in English | MEDLINE | ID: mdl-33715499

ABSTRACT

We herein report a rare case of a patient with a clival diploic vein arteriovenous fistula (AVF) associated with a posterior condylar canal AVF and discuss the radiological features of clival diploic vein AVF during decision-making on treatment strategies. A 69-year-old male patient with one-year history of pulsatile tinnitus was evaluated with magnetic resonance angiography, which revealed a dilated venous structure. Digital subtraction angiography revealed AVFs located in the clivus and posterior condylar canal. The clival diploic vein AVF was fed by the right internal maxillary artery and the petrous branch of middle meningeal artery and shed to the posterior condylar canal only through an intraosseous vein in the jugular tubercle. Although a catheter could not be navigated into the venous pouch in the clivus, the AVFs were successfully obliterated by transvenous embolization of the venous pouch in the posterior condylar canal.


Subject(s)
Arteriovenous Fistula , Embolization, Therapeutic , Aged , Angiography, Digital Subtraction , Arteriovenous Fistula/therapy , Cranial Fossa, Posterior/diagnostic imaging , Humans , Male , Meningeal Arteries
6.
Pediatr Emerg Care ; 37(7): 365-370, 2021 Jul 01.
Article in English | MEDLINE | ID: mdl-30211837

ABSTRACT

OBJECTIVES: The effectiveness of Japanese helicopter emergency medical services (HEMS) and interventions at the scene is not clear as regard children. For effective use of HEMS at the clinical scene, we need to clarify the characteristics of pediatric patients cared for by HEMS. Therefore, the objective of this study was to describe the characteristics of pediatric scene flights and to describe the procedures performed on the patients. METHODS: This was a retrospective cohort study based on the database for children aged younger than 18 years who were cared for by physician-staffed HEMS of Ibaraki prefecture, in Japan. We reviewed the database for air medical transports conducted at our institution from July 2010 to December 2016. RESULTS: During the 6.5-year period, the Ibaraki HEMS attended to 288 children. The median age of the children was 11 (interquartile range, 5-14) years. Of the total, 196 (68.1%) of the children had trauma-related injuries. The head was the most common site of significant injuries (12.4%). The most common cause of nontrauma incidents was seizure (9.0%). In 65.9% of the patients, the injury or illness was of mild or moderate severity at the scene. An intervention was applied at the scene in 76.0% of the cases: 75.1%, intravenous route; 6.9%, intubation; and 13.4%, drug administration. Of those patients, 29.1% were discharged from the emergency department. In-hospital mortality accounted for 1.5% (n = 2) of the cases. CONCLUSIONS: Although the condition at the scene of most of the pediatric patients transported by the physician-staffed HEMS was not severe, an intervention was frequently applied from the scene. Improving the dispatch criteria and monitoring compliance are needed for appropriate use of HEMS.


Subject(s)
Air Ambulances , Emergency Medical Services , Physicians , Adolescent , Aircraft , Child , Child, Preschool , Humans , Retrospective Studies
7.
PLoS One ; 15(8): e0237192, 2020.
Article in English | MEDLINE | ID: mdl-32785294

ABSTRACT

BACKGROUND: Helicopter emergency medical services' (HEMS) effectiveness for pediatric trauma patients remains unclear. We aimed to examine the relation between HEMS and reduced mortality in pediatric trauma patients. METHODS: This retrospective cohort study utilized data from the Japan Trauma Data Bank, a national multicenter clinical trauma database. Participants were aged <18 years, admitted between 2004 and 2015, and transported from the scene to the hospital by HEMS or ground emergency medical services (GEMS). We used a standardized mortality ratio (SMR) weight method, and fitted a marginal structural model to adjust for measured confounders. The SMR weight was calculated using the estimation of the propensity scores. A logistic regression model was used with the baseline independent variables to estimate the propensity score. RESULTS: Overall, 5,947 patients were identified in our study: 453 were transported by HEMS and 5,494 by GEMS. The mean injury severity score in the HEMS group was significantly higher than that in the GEMS group17.0 (Standard deviation = 11.0) vs 12.2 (Standard deviation = 9.2), p < .001. In-hospital mortality was higher in the HEMS group than that in the GEMS group in the unadjusted analysis (3.8% vs 1.3%, respectively; p < .001). After adjusting for covariates, HEMS transport was not associated with reduced hospital mortality. (odds ratio = 0.82, 95% confidence interval = 0.42-1.58). CONCLUSIONS: HEMS was not associated with reduced mortality among pediatric trauma patients compared with GEMS in this nationwide study. Further investigation is necessary to determine who clearly benefits from HEMS as compared to GEMS.


Subject(s)
Air Ambulances , Aircraft , Emergency Medical Services/methods , Hospital Mortality , Transportation of Patients/methods , Wounds and Injuries/mortality , Adolescent , Child , Child, Preschool , Databases, Factual , Female , Humans , Infant , Infant, Newborn , Injury Severity Score , Japan , Male , Mortality , Retrospective Studies , Time Factors
8.
Surg Neurol Int ; 11: 120, 2020.
Article in English | MEDLINE | ID: mdl-32494395

ABSTRACT

BACKGROUND: While recent randomized clinical trials have shown the efficacy of mechanical thrombectomy for acute large vessel anterior cerebral occlusion, cases in patients with a subarachnoid hemorrhage (SAH) were excluded from the study. CASE DESCRIPTION: A 58-year-old man presented with a SAH as a result of a ruptured middle cerebral artery aneurysm. Coil embolization was performed, and a right intracranial angiography showed remnants of an aneurysmal neck. However, the following angiography also revealed a thromboembolic complication that occurred in the same territory as the ruptured aneurysm. The patient underwent a rescue mechanical thrombectomy under the working projection. We deployed a retrieval stent without covering the aneurysmal neck. The occluded vessel was recanalized without any hemorrhagic complication. Due to minimal intracerebral infarction, the patient had good outcomes. CONCLUSION: Mechanical thrombectomy is a useful option to retrieve a clot from an occluded intracranial vessel located near a ruptured aneurysm. Approaching the clot at the working projection is important to ensure safety in the setting of a ruptured aneurysm.

9.
World Neurosurg ; 132: e812-e819, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31404689

ABSTRACT

BACKGROUND: Few reports have focused on chronic subdural hematoma (CSDH) in the very elderly, who have lived beyond average life expectancy. Our aim is to appraise treatment outcomes of burr-hole craniotomy for CSDH in the elderly, focusing on cure, recurrence, and complications. METHODS: Fifty patients ≤79 years of age (group A) and 73 patients ≥80 years of age (group B) were studied. Recurrence was defined as requiring reoperation for hematoma regrowth or symptomatic failure. A cure was regarded as having been achieved in the absence of hematoma on postoperative computed tomography. Complications were defined as any harmful event related to the treatment procedure for CSDH. RESULTS: Cure was documented in 31 patients in group A (63%) and 24 patients in group B (33%) (P = 0.0017). Median intervals to cure were 2.76 and 3.73 months, respectively (P = 0.06). Cumulative cure rates were 51%/76% and 36%/59%, respectively, at the sixth/twelfth postoperative months. Recurrence was documented in 2 patients (4%) and 11 patients (15%), respectively (P = 0.07). Median intervals to recurrence were 0.81 and 1.25 months, respectively (P = 0.049). Cumulative recurrence-free rates were 96%/92% and 87%/75%, respectively, at the third/sixth postoperative months. Complications were observed in 2 patients (4%) and 4 patients (5%), respectively (P = 1.00). CONCLUSIONS: With advancing age, CSDH might show a greater tendency to recur and a longer time is required to achieve a cure. However, complications developed only in high-risk patients. Thus, surgical treatment for CSDH in elderly patients, even those who have lived beyond life expectancy, might provide acceptably effective results.


Subject(s)
Hematoma, Subdural, Chronic/surgery , Trephining/methods , Age Factors , Aged , Aged, 80 and over , Cohort Studies , Female , Follow-Up Studies , Hematoma, Subdural, Chronic/mortality , Humans , Kaplan-Meier Estimate , Life Expectancy , Male , Postoperative Complications/epidemiology , Recurrence , Reoperation/statistics & numerical data , Retrospective Studies , Treatment Outcome , Trephining/mortality
11.
J Clin Neurosci ; 32: 41-6, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27523585

ABSTRACT

We present a retrospective analysis of endovascular treatments for posterior cerebral artery (PCA) aneurysms and discuss the susceptibility of a fetal-type PCA to vascular insufficiency after parent artery occlusion. Among 1207 aneurysms treated with endovascular therapy between March 1997 and March 2013 in our institution, 10 patients (0.8%) presented PCA aneurysms. The principal strategy was to employ selective coil embolization for the aneurysm. However, in certain cases of fusiform or dissecting aneurysms, we performed parent artery occlusion with coils. Clinical and radiological data were collected from hospital charts and evaluated retrospectively. The mean age was 52.7±15.6years (range, 12-65years). Five patients (50%) were admitted with a subarachnoid hemorrhage, and one patient presented with slowly developing paralysis. The remaining four patients were diagnosed incidentally. Five patients underwent selective coil embolization, and five patients underwent parent artery occlusion. All endovascular therapies were successfully performed. However, two patients in the parent artery occlusion group suffered cerebral infarction, and both patients exhibited a fetal-type PCA. The remaining three patients in the parent artery occlusion group exhibited an adult-type PCA and did not suffer a cerebral infarction. Endovascular treatment with either selective coil embolization or parent artery occlusion is safe and effective as the long as the anatomical type of the PCA is considered. Patients with a fetal-type PCA may develop vascular insufficiency upon parent artery occlusion. Neurosurgeons should attempt to preserve the parent artery using a flow-diverting stent or stent-assisted technique for a fetal-type PCA aneurysm.


Subject(s)
Embolization, Therapeutic/adverse effects , Intracranial Aneurysm/therapy , Posterior Cerebral Artery/diagnostic imaging , Adolescent , Adult , Aged , Cerebral Angiography , Child , Female , Humans , Intracranial Aneurysm/diagnostic imaging , Male , Middle Aged , Posterior Cerebral Artery/pathology , Stents/adverse effects
12.
Resuscitation ; 85(3): 315-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24291510

ABSTRACT

OBJECTIVES: Bystander-initiated cardiopulmonary resuscitation (CPR) has been reported to increase the possibility of survival in patients with out-of-hospital cardiopulmonary arrest (OHCA). We evaluated the effects of CPR instructions by emergency medical dispatchers on the frequency of bystander CPR and outcomes, and whether these effects differed between family and non-family bystanders. METHODS: We conducted a retrospective cohort study, using Utstein-style records of OHCA taken in a rural area of Japan between January 2004 and December 2009. RESULTS: Of the 559 patients with non-traumatic OHCA witnessed by laypeople, 231 (41.3%) were given bystander CPR. More OHCA patients received resuscitation when the OHCA was witnessed by non-family bystanders than when it was witnessed by family members (61.4% vs. 34.2%). The patients with non-family-witnessed OHCA were more likely to be given conventional CPR (chest compression plus rescue breathing) or defibrillation with an AED than were those with family-witnessed OHCA. Dispatcher instructions significantly increased the provision of bystander CPR regardless of who the witnesses were. Neurologically favorable survival was increased by CPR in non-family-witnessed, but not in family-witnessed, OHCA patients. No difference in survival rate was observed between the cases provided with dispatcher instructions and those not provided with the instructions. CONCLUSIONS: Dispatcher instructions increased the frequency of bystander CPR, but did not improve the rate of neurologically favorable survival in patients with witnessed OHCA. Efforts to enhance the frequency and quality of resuscitation, especially by family members, are required for dispatcher-assisted CPR.


Subject(s)
Cardiopulmonary Resuscitation/standards , Emergency Medical Service Communication Systems , Family , Out-of-Hospital Cardiac Arrest/therapy , Aged , Aged, 80 and over , Cohort Studies , Female , Humans , Male , Middle Aged , Retrospective Studies , Treatment Outcome
13.
Neurol Med Chir (Tokyo) ; 52(9): 691-4, 2012.
Article in English | MEDLINE | ID: mdl-23006889

ABSTRACT

Sufficient bone decompression of osteophytes is important for positive functional outcomes in anterior cervical spine surgery. Achieving good alignment and bone fusion in anterior cervical decompression and fusion requires a bone graft bed of the optimum size and shape. We have developed a stainless steel instrument named the anterior fusion spinal fork, which is designed to aid in accurately drilling the bone cavity, thus enabling selection of the correct size of bone graft or bone graft substitutes. The device has an open design with 4 prongs, and resembles a three-dimensional fork. This instrument assists in guiding the direction of drilling, and marking the drilling point of the graft cavity with pyoctanin markers. We have used this instrument in 40 cases of anterior cervical spine surgery using the modified Smith-Robinson procedure since March 2000. This simple instrument allowed us to design and construct a bone graft cavity of the correct size and shape for iliac bone graft or bone graft substitutes for anterior cervical spine surgery.


Subject(s)
Bone Transplantation/instrumentation , Cervical Vertebrae/surgery , Decompression, Surgical/methods , Diskectomy/methods , Spinal Cord Compression/surgery , Spinal Fusion/methods , Adult , Aged , Cervical Vertebrae/diagnostic imaging , Coloring Agents , Durapatite , Equipment Design , Female , Gait Disorders, Neurologic/etiology , Gentian Violet , Humans , Hypesthesia/etiology , Male , Middle Aged , Neck Injuries/complications , Neck Injuries/surgery , Prostheses and Implants , Radiography , Retrospective Studies , Spinal Cord Compression/etiology , Spinal Osteophytosis/complications , Spinal Osteophytosis/diagnostic imaging , Spinal Osteophytosis/surgery , Spondylosis/complications , Spondylosis/surgery
14.
Hum Exp Toxicol ; 29(5): 427-9, 2010 May.
Article in English | MEDLINE | ID: mdl-20068013

ABSTRACT

A 27-year-old female nurse intravenously injected 5 mL of cigarette soakage solution that contained approximately 5.7 mg nicotine, in a suicidal attempt. Clinical manifestations consisted of nausea, palpitation, abdominal pain, repeated vomiting, and diarrhea. She remained fully conscious during this episode. About 7 hours later, she visited emergency department on foot and received fluid infusion for dehydration. She fully recovered at night of the day. This is the first documented report of acute nicotine poisoning due to intravenous injection of cigarette soakage in humans. Signs and symptoms appeared immediately after the injection, but this case seemed to be relatively mild in terms of clinical manifestation. The elimination half-life of nicotine seems to be short, that is, less than 1 hour. Therefore, if initial treatment is appropriate and the patient can survive acute phase of nicotine poisoning, prognosis is good.


Subject(s)
Nicotiana/chemistry , Nicotine/poisoning , Plant Poisoning/etiology , Adult , Female , Fluid Therapy , Half-Life , Humans , Injections, Intravenous , Nicotine/pharmacokinetics , Plant Extracts/chemistry , Plant Extracts/pharmacokinetics , Plant Extracts/poisoning , Plant Poisoning/physiopathology , Plant Poisoning/therapy , Suicide, Attempted
15.
Anticancer Res ; 23(6D): 5231-5, 2003.
Article in English | MEDLINE | ID: mdl-14981995

ABSTRACT

BACKGROUND: In boron neutron capture therapy, blood boron concentration is the key factor to calculate radiation dose, however, blood sampling is difficult during neutron irradiation. MATERIALS AND METHODS: The prediction of blood boron concentrations for BNCT treatment planning has been prospectively investigated using patient data obtained at first craniotomy after the infusion of a low dose of sodium undecahydroclosododecaborate. RESULTS: The boron biodistribution data showed a biexponential pharmacokinetic profile. If the final boron concentration at 6 or 9 hours after the end of the infusion is within the 95% confidence interval of the prediction, direct prediction from biexponential fit will reduce the error of blood boron concentrations during irradiation to around 6%. CONCLUSION: Actual boron concentrations during BNCT were reasonably and accurately predictable from the test data.


Subject(s)
Astrocytoma/blood , Boron Neutron Capture Therapy , Boron/blood , Brain Neoplasms/blood , Glioblastoma/blood , Adult , Aged , Astrocytoma/radiotherapy , Astrocytoma/surgery , Boron/pharmacokinetics , Brain Neoplasms/radiotherapy , Brain Neoplasms/surgery , Combined Modality Therapy , Female , Glioblastoma/surgery , Glioblastoma/therapy , Humans , Male , Middle Aged , Prospective Studies , Tissue Distribution
16.
In. Hamada, M, ed; O'Rourke, T, ed. Proceedings from the Sixth Japan-U.S. Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures Against Soil Liquefaction. Buffalo, NY, U.S. National Center for Earthquake Engineering Research, Sep. 1996. p.243-58, ilus, tab.
Monography in En | Desastres -Disasters- | ID: des-9696

ABSTRACT

Parameters which influence the settlement of the tower of transmission line are evaluated. Dynamic centrifuge tests and tests for obtaining fundamental properties of sand satured with different pore fluids (water, 50cst silicon oil) are carried out. The letter tests indicate:(i) In cyclic triaxial tests, there is no difference between the samples satured with water and silicon oil:; (ii) To satisfy the law of similarity, it is preferable to use silicon oil instead of water in centrifuge tests.(AU)


Subject(s)
Soil , Methods , 34661 , Centrifugation
17.
In. Hamada, M, ed; O'Rourke, T, ed. Proceedings from the Sixth Japan-U.S. Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures Against Soil Liquefaction. Buffalo, NY, U.S. National Center for Earthquake Engineering Research, Sep. 1996. p.275-88, ilus, tab.
Monography in En | Desastres -Disasters- | ID: des-9698

ABSTRACT

Very severe lateral flow occurred in the liquefied ground behind quay walls during the 1995 Hyogoken-nambu (Kobe) earthquake. Shaking table tests were conducted under several conditions to study the mechanism of the lateral flow. A soil container with a model quay wall and a model pile was used. The model quay wall was moved quickly or slowly just after the occurrence of liquefaction. Displacement of the top of the pile was affected by the speed of the movement of the wall and soil density. The effectiveness of densification of the ground behind the quay wall in preventing lateral flow was also studied.(AU)


Subject(s)
Engineering , Soil , Methods , Earthquakes , Japan , 28574
18.
In. U.S. National Center for Earthquake Engineering Research (NCEER). Proceedings from the fifth U.S.-Japan workshop on earthquake resistant design of lifeline facilities and countermeasures against soil liquefaction. Buffalo, N.Y., U.S. National Center for Earthquake Engineering Research (NCEER), 1994. p.181-98, ilus. (Technical Report NCEER, 94-0026).
Monography in En | Desastres -Disasters- | ID: des-7459

ABSTRACT

Behavior of sand after liquefaction is discussed and formuled. Material properties that are usually assumed constant, such as internal friction angle, is ahown to change due to cyclic loading causing liquefaction. It is also shown that regions with very small stiffness appears by the cyclic loading. They may expand several ten percents, which causes liquefaction-induced large permanent displacement. A simlified model is introduced and improved so as to be able to take into new features such as change of material property and appearance of low stiffness region. The agreement of the numerical calculation and test are very good. Future research needs for evaluating the amount of liquefaction-induced permanent displacement more precisely are also pointed out.(AU)


Subject(s)
Sandy Soils , Soil Mechanics , 24975 , Engineering
19.
In. U.S. National Center for Earthquake Engineering Research (NCEER). Proceedings from the fifth U.S.-Japan workshop on earthquake resistant design of lifeline facilities and countermeasures against soil liquefaction. Buffalo, N.Y., U.S. National Center for Earthquake Engineering Research (NCEER), 1994. p.249-65, ilus, tab. (Technical Report NCEER, 94-0026).
Monography in En | Desastres -Disasters- | ID: des-7463

ABSTRACT

The stress-strain relationships of sand after liquefaction were studied by conducting torsional shear and triaxial compression tests under several conditions. A prescribed number of cyclic loadings were applied first, then a monotonic loading was applied in undrained conditions. The stress-strain curves were affected by the accumulated excess pore pressure ratio and by the severity of liquefaction. The shear and secant modulus decreased to less than 1/1000 due to liquefaction. The shear strain increased more than 10


with very low stress in the liquefied specimen. And, there exists a so called "reference strain at resistance transformation, " which increases with decreases in soil density, severity of liquefaction and fines content, and with increase with confining pressure.(AU)


Subject(s)
Sandy Soils , Soil Mechanics , Statistics as Topic , 24975 , Research
20.
In. U.S. National Center for Earthquake Engineering Research (NCEER). Proceedings from the fifth U.S.-Japan workshop on earthquake resistant design of lifeline facilities and countermeasures against soil liquefaction. Buffalo, N.Y., U.S. National Center for Earthquake Engineering Research (NCEER), 1994. p.665-77, ilus. (Technical Report NCEER, 94-0026).
Monography in En | Desastres -Disasters- | ID: des-7490

ABSTRACT

Many manholes and sewage pipes were floated due to liquefaction during the 1993 Kushiro-oki earthquake in Japan. To study the mechanism of the floatation, several shaking table tests were carried out under several conditions of soil densities, specific gravities of pipes, water levels and diameters of pipes. Tests were also conducted on the model grounds in which a trench was excavated and then backfilled with loose sands. Test results show that the speed and the height of floatation are affected by soil density, the specific gravity of the pipe or manhole, water level, and width and depth of the trench.(AU)


Subject(s)
Earthquakes , Pipelines , Wastewater , Japan , Saturated Soils
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