为探究隧道管棚注浆钢管不同支护参数对管棚支护承载能力的影响，引入Pasternak双参数模型构建出更符合实际情况的管棚支护力学模型，通过多组室内试验，对管棚在不同注浆钢管管径、壁厚、注浆饱满度及加设钢筋笼条件下的承载能力进行定量研究。研究表明： 1）管棚注浆钢管支护参数中，对管棚承载能力的影响排序为： 管径>注浆饱满度>壁厚>钢筋笼。2）增大管棚注浆钢管管径可大幅提高管棚的承载能力，相比管径为108 mm的管棚，管径为159、219、299 mm时管棚承载能力分别增大183.58%、398.62%、874.86%。3）管棚钢管注浆不饱满会较大程度削弱管棚的承载能力，钢管注浆饱满度由100%降至75%、50%时，管棚承载能力分别降低29.8%、34.5%，注浆饱满度为50%时管棚的承载能力与未注浆时相差不大。4）管棚钢管壁厚和钢筋笼加设与否对管棚的承载能力影响较小。因此，在实际工程中，可通过增大管棚钢管管径提升管棚的承载能力，通过减小管棚钢管壁厚及不加设钢筋笼节约用钢量。
To examine the influence of
various support parameters of pipe-roof
grouting steel pipes on the bearing capacity of tunnel pipe-roof supports, the Pasternak two-parameter
model is adopted to develop an accurate mechanical model of tunnel pipe-roof supports. Indoor experiments are conducted to assess the
bearing capacities of pipe-roof grouting steel pipes
with varying pipe diameters, wall thicknesses, and grouting fullness, as well
as with and without reinforced steel cages. The experimental results reveal the
following: (1) The influence of various support parameters of pipe-roof grouting steel pipes on the bearing capacity of the pipe roof
follows the order of pipe diameter > grouting fullness > wall thickness
> steel cage. (2) Increasing the pipe diameter significantly improves the
bearing capacity of the pipe roof. For instance, compared to a pipe diameter of
108 mm, pipe diameters of 159, 219, and 299 mm increase the bearing capacity of
the support by 183.58%, 398.62%, and 874.86%, respectively. (3) The grouting
fullness substantially impacts the bearing capacity of the support.
Specifically, as the grouting fullness of the pipe roof decreases from 100% to
75% and then to 50%, the bearing capacity drops by 29.8% and 34.5%,
respectively. However, at the grouting fullness of 50%, the bearing capacity of
the pipe roof is similar to that of a nongrouted pipe roof. (4) The reinforced
steel cage and the wall thickness of the pipe roof slightly impact the bearing
capacity of the pipe roof. Hence, in practical applications, increasing the
pipe diameter is the most efficient approach for enhancing the bearing capacity
of the pipe roof. Furthermore, reducing the wall thickness of the steel pipe
can lower steel consumption without requiring a reinforced steel cage.
