The adhesion is traditionally defined as the strength
of an interface between two materials, for instance between
rock and shotcrete. However, in many cases the
location of the failure surface will vary depending on
the strength of the contact zone, the tensile strength of
the rock and the tensile strength of shotcrete layer. A
field study by Karlsson (1980) showed that only in
32% of the 238 tests the whole failure was located in
the contact area, see Fig. 2. The rock types were mainly
gneiss (227 tests) and in a few cases (11 tests) granite.
The adhesion strength mainly depends on treatment
(cleaning), roughness of the rock surface, mineral composition
of the rock and shotcreting technique. The
shotcrete technique includes the skill of the operator
which is of great importance. After mechanical scaling,
the rock surface has to be cleaned in order to achieve adhesion
strength between the rock and the shotcrete.
During the last decade a method, which is a substitute
for the mechanical scaling and the subsequent water
cleaning, called water jet-scaling, has been tested in order
to assess the potentials of the method to provide
an improved adhesion. Water-jet scaling was tested as
a treatment method in a tunnel project at Hallandsas
in Sweden (Lundmark and Nilsson, 1999). The results
showed that the water jet-scaling gave a higher adhesion
(a) (b) (c)
Fig. 1. Promotion of block interlock, modified after Stacey (2001). (a) Shear and normal stress in the shotcrete-
rock interface. (b) Tension in surface
support and normal stress in shotcrete-rock interface. (c) Penetration of shotcrete into joints and cracks.
34 L. Malmgren et al. / Tunnelling and Underground Space Technology 20 (2005) 33–48
strength than mechanical scaling and cleaning. However,
the scatter in the adhesion strength was so large that it
was difficult from statistical analysis to conclude
whether the adhesion strength was significantly higher
or not. In a project conducted at Colorado School of
Mines (Kuchta, 2002), the adhesion strength on a concrete
wall was four times higher when cleaned with a
water pressure of 21 MPa compared to cleaning with a
water pressure of 0.7 MPa.
翻譯如下:
2 。粘接強度 <br>粘附是傳統定義為力量 <br>對兩種材料之間的相互關系，例如之間 <br>巖石和混凝土。然而，在許多情況下， <br>位置破裂面將取決於 <br>強度的接觸帶，拉伸強度 <br>巖石和拉伸強度噴層。字母a <br>實地研究的卡爾森（ 1980年）表明，只有在 <br> 32 ％的238測試整個失敗位於 <br>接觸面積，見圖。 2 。巖石類型主要 <br>片麻巖（ 227測試）和在少數情況下（ 11測試）花崗巖。 <br>結合強度主要取決於治療 <br> （清潔） ，粗糙的巖石表面，礦物組成 <br>巖石噴技術。那個 <br>噴射混凝土技術包括技術的運營商 <br>這是非常重要的。機械縮放， <br>巖石的表面，要清除，以實現粘附 <br>實力之間的巖石和混凝土。 <br>在過去十年中的壹種方法，這是壹種替代品 <br>機械結垢和隨後的水 <br>幹洗，稱為水射流尺度，已經過測試，以便 <br>評估的潛力，提供方法 <br>改善粘連。水射流縮放是考驗 <br>壹種治療方法在隧道工程Hallandsas <br>在瑞典（倫德馬克和尼爾森， 1999年） 。結果 <br>結果表明，水射流尺度了更高的黏附 <br> （壹） （二） （三） <br>圖。 1 。促進聯鎖塊，修改後斯泰西（ 2001年） 。 （壹）剪切和正常應力噴 <br> <br>巖石界面。 （二）在表面張力 <br>支持和正常應力噴巖界面。 （三）滲透噴到關節和裂縫。 <br> 34屬馬爾姆格倫等。 /隧道和地下空間技術20 （ 2005 ） 33-48段 <br>強度比機械尺度和清潔。但是， <br>分散的粘接強度非常大，它 <br>很難從統計分析得出結論 <br>是否粘接強度明顯高於 <br>或沒有。在項目進行科羅拉多學院 <br>地雷（ Kuchta ， 2002年） ，粘接強度的混凝土 <br>墻高4倍時，清理了 <br>水壓力21兆帕比較清潔的 <br>水壓力0.7兆帕。