Dewatering Cofferdam for Construction of Olmsted Locks

Twin 110-ft×1,200-ft (SI unit conversions are provided in the Appendix) locks and a dam are being constructed in the Ohio River near Olmsted, IL. Construction of these locks required digging a 1,200-ft-wide and 2,200-ft-long excavation in the Ohio River to 100 ft below the design river stage. The size of the cofferdam required for lock construction, and the depth of excavation, made control of groundwater of paramount importance to excavation safety. The work included removing and/or controlling all ground and surface water within the cofferdam; controlling seepage through or beneath the coffercells and from the open cut along the Illinois bank; reducing the artesian head in an underlying stratum of highly jointed, indurated clayey silt and/or siltstone; and lowering the water level in the coffercells. The dewatering was accomplished by installing and pumping deep wells with submersible pumps, with vacuum, within the cofferdam area. The dewatering system was pump tested and evaluated before unwatering the excavation. Evaluation of the pump test data showed that the dewatering system as designed and installed would be adequate for the maximum design river stage with the addition of a few wells in the bottom of the excavation.     

Modeling Ice Passage at Navigation Locks

Physical and numerical models were used to assess ice passage at navigation locks, focusing on key factors such as the design of the lock filling and emptying system and the intakes to the lock filling culverts. Unconventional ice passage techniques such as manifolds in the miter gates were also evaluated. Physical model results were compared to field observations and to a parallel series of tests using the DynaRICE ice-hydraulic numerical model. The study focused on three general ice processes at locks: (1) ice accumulating near culvert intakes during lock filling; (2) drawing ice into the lock chamber; and (3) flushing ice out of the lock. Ice accumulation thickness in the upper lock approach was found to be the most important parameter affecting ice passage into the lock chamber. Physical and numerical model results compared reasonably well, proving DynaRICE to be a useful tool for assessing ice passage for new lock designs.     

Ice Adhesion to Locks and Dams: Past Work; Future Directions?

Adhesion of ice to surfaces creates problems for many industries, including aviation, hydropower, telecommunications, navigation, electrical distribution, and all forms of transportation. Specific problems at locks and dams include ice buildup on lock walls and miter gates, and spillway gate freeze up, preventing opening on short notice. At present, ice removal techniques are both costly and time-consuming. In an effort to reduce the cost, time, and physical labor associated with ice removal, much research on ice adhesion has been done. This work ranges from theoretical studies to microscopic investigations and full-scale field tests. The main focus of all of these studies is how to lower ice’s adhesive strength, thus easing ice removal. Three principal methods to lower ice’s adhesive strength have been pursued—electrical, chemical, and mechanical. Of the three methods, the mechanical removal of ice has received the least amount of attention. Three approaches have been taken with regard to electrical methods. They are using heaters, creating an electrical pulse that mechanically breaks the ice, and applying a direct current bias to change the ice’s adhesion. The search for a low adhesive coating or material has by far received the most attention of any method pursued for lowering ice’s adhesive strength. A class of chemicals containing polysiloxanes has shown promise in providing a low adhesion surface. Based on this review, we recommend that an electroexpulsion method developed for the space shuttle and a newly formulated polysiloxane be tested as to their feasibility in the lock and dam environment.     

大中型水利枢纽船闸自重估算公式的研究

本文在收集大量的大中型水利枢纽船闸人字门的数据资料基础上,运用二元非线性回归分析的方法,演出一组估算人字门自重的简明经验公式,经验证具有较好的可靠性。     

Oracle DML封锁等待原因分析和应用中的处理方法

文章分析了ORACLE数据库DML(DATA MANIPULATION LANGUAGE数据操作语言)封锁方法,解释了DML封锁导致的锁等待的原因,指出了ORACLE数据库对于锁等待处理方式上不完善的地方,并提出了在应用中的一种处理方法。     

Oracle DML封锁等待原因分析和应用中的处理方法

文章分析了ORACLE数据库DML（DATA MANIPULATION LANGUAGE数据操作语言）封锁方法，解释了DML封锁导致的锁等待的原因，指出了ORACLE数据库对于锁等待处理方式上不完善的地方，并提出了在应用中的一种处理方法。     

Hydraulic Design of a Longitudinal Culvert for Lock Filling and Emptying Systems

The U.S. Army Corps of Engineers is planning navigation improvements for many projects to meet predicted increases in tow traffic. Some of these improvements include the addition or replacement of the navigation lock. Innovative design and construction techniques are being investigated to try and reduce construction costs as well as operation and maintenance costs. The Corps identified that a savings in lock construction could be achieved if the conventional concrete gravity lock walls with culverts inside them could be replaced with thin walls and longitudinal culverts located inside the chamber. This culvert design was designated the In-Chamber Longitudinal Culvert System (ILCS). An extensive research effort led to the development of the ILCS design. This paper provides a brief summary of the research results and the accompanying design guidance developed for low to medium lift ILCS locks. The guidance includes culvert location; port size, location, and spacing; port extensions; culvert-roof overhang; and wall baffles. Lock chamber performance characteristics, based on acceptable filling and emptying operations determined using a laboratory model, are also presented. The ILCS is a feasible design based on the hydraulic performance determined from the investigation.     

明清山东运河船闸的空间分布与管理运作

山东运河地势起伏较大导致河道比降大,必须设置船闸以克服水位落差以保证漕船顺利通航。明清山东运河设有大量船闸,朝廷制定了一系列制度保证船闸的正常运作。本文从船闸的空间分布、管理机构设置以及如何运作等方面详细论述了明清山东运河船闸,并探讨了船闸的空间分布与管理运作的关系。     

基于SYBASE SQL Server的页锁表锁及死锁研究

主要讨论了SYBASE SQL Server的锁，分析了引起死锁的各种可能性，并且提出了避免死锁产生、提升系统性能的实施方法。     

A mathematical hydraulic model of the River Nene - A canalized,and heavily controlled river

The paper describes a mathematical hydraulic model of the River Nene in East Anglia, England. This river, which is typical of many in that predominantly flat region, is canalized and subsequently heavily controlled. The routing model has been developed in order to investigate the effect of improvements that could be made to the river to reduce the frequency of flooding. The model is in its final stage of development and results are presented of a flood that was monitored in March 1982.