Specification for Polyethylene Stay In Place Form System for End Walls for Drainage Pipe

2021 ◽  
Author(s):  
Keyword(s):  
Drainage Pipe ◽  
Form System

Classification, Causes of Tunnel Frost Damages in Cold Region and Several New Technologies to Prevent them

2012 ◽  
Vol 170-173 ◽  
pp. 1504-1510 ◽  
Author(s):  
Zhe Ji ◽  
Kang Cheng Lu ◽  
Chao Chao Ma
Keyword(s):  
Structural Damage ◽  
New Technologies ◽  
Electric Heating ◽  
Drainage Water ◽  
Good Choice ◽  
Large Temperature ◽  
Freezing Damage ◽  
Cold Region ◽  
Cold Regions ◽  
Drainage Pipe

This paper classifies the tunnel frost damages and discusses their causes, especially the causes of lining structural damage for freezing and they are classified into two categories: the outer freezing damage and the inner freezing damage of lining. The analysis shows that the former has a little effect on the structure, but the latter has big threat. For the phenomenon that cracks frequently occur in the tunnel lining of cold regions, some measures to prevent cracks are presented, including reducing adverse constraints in the process of temperature change and preventing large temperature stress. In cold regions, it is unsuitable to adopt back paste-type water-stops to prevent the leakage from lining construction joints, and a good choice is to utilize the buried drainage water-stops. The ring drainage pipes directly connect with the central drainage pipe, and thermal insulating layer with belt shape is set along the ring drainage pipes in some sections where surrounding rock is water-rich and the middle and lower part of the ring drainage pipe are easily frozen. In sections with high potential freezing threat, an anti-freezing plan is offered that electric heating wires are installed behind the lining wall. The test shows that above techniques have good effects in cold region tunnels.

The Plecnik´s Reconstructed Footbridge at Prague Castle, Eleven Years after

2018 ◽  
Vol 776 ◽  
pp. 197-200
Author(s):  
Vítězslav Vacek ◽  
Jiří Kolísko
Keyword(s):  
Drainage Pipe

An example of a successful reconstruction of the small but important and culturally significant structures Plecnik’s footbridge located on the premises of Prague Castle is discussed in this paper. The building was severely disrupted for 10 years after a previous reconstruction. This damage and degradation was caused mainly as a result of faults incorrectly designed new waterproofing and water freezing in the new drainage pipe bridge. Technically properly designed and in 2006, well made reparations, resulting problems removed and for 10 years after completion fulfils its function perfectly and reliably protects valuable object

scholarly journals Investigation and Analysis on Crystallization of Tunnel Drainage Pipes in Chongqing

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Xuefu Zhang ◽  
Yuanfu Zhou ◽  
Bin Zhang ◽  
Yuanjiang Zhou ◽  
Shiyang Liu
Keyword(s):  
Groundwater Level ◽  
Laboratory Tests ◽  
Support Structure ◽  
Sem Images ◽  
Tunnel Support ◽  
Site Investigations ◽  
Inner Surface ◽  
Drainage Pipe ◽  
Under Construction

A lot of crystallizations exist on the inner wall of tunnel drainage pipes in Chongqing. Tunnel support structure often bears larger load than usual because the tunnel drainage pipes are blocked easily by the crystals and the groundwater level would rise. In order to investigate what the crystals are, site investigations and laboratory tests of crystals and groundwater were completed. Some valuable results have been obtained. Firstly, the crystallizations are usually discovered in drainage pipe exits of tunnels which are under construction in Chongqing. Furthermore, the results of XRD have confirmed that the crystals are calcite. And calcite morphology could be found in most SEM images. But there are other morphologies in these images other than calcite because calcite is often influenced by some factors, such as important ions in groundwater, pH of groundwater, kinetics effect, and so on. Finally, some steps and solutions to solve blocking of tunnel drainage pipes caused by crystallization are suggested. One of the best solutions is that some special materials which could prevent crystals from being attached to pipes are coated on the inner surface of drainage pipes. The results could contribute to understand the crystallization phenomenon profoundly and help solve the similar situations of tunnel drainage pipe blocking.

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