碼崙溪河床質剪力及摩擦試驗之相關性研究

STUDY ON RELATION OF THE SHEAR TEST AND A FRICTIONAL TEST FOR RIVER-BED MATERIALS OF MA LUNG STREAM

林親義(Chin-I Lin) ； 謝豪榮(Hao-Jung Shieh)

《中華水土保持學報》 16卷1期 (1985/03) Pp. 87-98

https://doi.org/10.29417/JCSWC.198503_16(1).0008

摘要

爲探求在堆積層河床上興建構造物之穩定性，應先瞭解河床堆積泥砂具有之特性；欲瞭解其特性，宜由採樣、試驗分析着手；因此乃利用採自本省東北部之碼崙溪河床質，取粒徑小於9.52 mm者，經篩分後，作剪力及摩擦推力試驗，以求得河床質各粒徑別之內摩擦角，及其與混凝土間之摩擦係數，以供在堆積層河床上設計防砂壩作滑動阻抗力檢算之參考。經試驗分析結果，獲致下列結論：河床質之內摩擦角或河床質與壩底接觸面間之摩擦係數爲影響壩體滑動之主要因素。在飽和狀態下，河床質粒徑在9.52 mm以下各粒徑別之內摩擦角，隨粒徑之增大而增加；河床質粒徑為0.25〜9.52 mm時，其與混凝土接觸面之摩擦係數，隨粒徑之增大而增加，隨垂直荷重之增加而減少，與混凝土樸型底面積爲230 cm^2丶281 cm^2之大小無顯著差異。飽和狀態下，河床質粒徑在0.25〜9.52 mm間同粒徑別之內摩擦角，及其與光滑混凝土間之摩擦係數，有F_u = K FØ之關係存在。式中F_u爲河床質與光滑混凝土間之摩擦係數K為摩擦係數與內摩擦角之相關係數FØ爲河床質之內摩擦角（正切之值）

關鍵字

粒徑 ； 內摩擦角 ； 摩擦係數 ； 碼崙溪 ； 剪力試驗 ； 摩擦試驗

並列摘要

To determine the stability of the construction built on the alluvial river-bed, firstly we need to understand the feature of sediments of alluvial river-bed. In this study, based on results of some laboratory tests. Sampled of the river-bed materials from Ma Lung Stream of the Northeastern Taiwan with particle size less than 9.52 mm. were colected. Then using the shear test and a frictional test were made to measure the angle of internal friction for various particle sizes and the coefficient of skin friction between materials and concrete. The sliding resistant force for designing the Sabo-dams on the alluvial river-bed in the watershed can be further calculated. From these experimental results, we can draw the following conclusios: 1. Either the angle of internal friction of river-bed materials or the coefficient of skin friction between river-bed materials and contact surface of dam base is the main factor of affecting dambody sliding 2. For the particle sizes of river-bed materials less than 9.52 mm. in saturated condition, the increase in the angle of internal friction is directly proportional to particle size. Under the same condition, for the particle size ranging from 0.25-9.52 mm. the increase in the coefficient of skin friction with concrete construction surface is directly proportional to the particle size, but inversely proportional to the normal load. However, not related significantly to difference between river-bed materials and base area of concrete model contact surface 230cm^2, 281cm^2. 3. Under saturated conditions for the same particle size, there exists a relationship between the angle of internal friction and the coefficient of skin friction: Fu=KFØ. Where, Fu is the coefficient of skin friction between river-bed material and smooth concrete surface K is a relative coefficient between the coefficient of skin friction and the angle of internal friction FØ is the angle of internal friction with river-bed material As for the particle sizes of river-bed materials over 9.52mm. the angle of internal friction, the skin friction coefficient, and the natural alluvial angle of internal friction should be continued to search for, because they are the basic data for calculating sliding resistant force in the design of the construction.

並列關鍵字

Partiele size ； Angle of internal friction ； coefficient of skin friction ； Ma-Lung stream ； shear test ； a frictional test