高边坡路堑控制baopo施工技术

　　 1、工程概况
　　国道**线**至**段改建工程L1合同段全长12km，土石方总量565000m3，有多处深挖石质路堑，其中**路堑（k1051＋720～k1052＋020）断面底宽14.5m，最大边坡高度33m，是全线最大的挖方段，路堑岩体为中元古界燧石条带白云岩，节理裂隙发育，有松散的软弱夹层，对边坡稳定十分不利。该baopo工点紧临国道**线，线路右侧有密集村庄，施工环境比较复杂，对控制baopo的要求高，再加上工程量集中，工期紧，施工难度比较大。
　　2、baopo方案
　　路堑边坡设计率从上至下为1：1、1：0.75、1：0.5，每10m台阶高度设置2m宽的碎落台。根据工程特点，结合进度要求和资源配置等因素，采取按台阶高度分层分段多作业面同时开挖的施工方案，施工中采用深孔微差baopo技术，先拉通路堑主槽，两侧边坡预留的1m～2m宽的岩体不爆，作为中部主爆体的隔墙，以减少大baopo对边坡的损伤，同时预留的岩体光面baopo时，可以根据主爆体的baopo情况和岩石性质更准确地选择baopo参数，提高边坡的光爆效果。
　　2•1主爆区控制baopo参数
　　采用潜孔钻机垂直钻孔，钻孔直径d＝100mm，炮孔布置如图1所示。
High Slope Controlled Blasting Techniques

1, Project Overview
National Highway ** line ** to ** Contract for Rebuilding the L1 segment length 12km, earthwork volume 565000m3, there are multiple root out the stone cutting, which ** Cut (k1051 +720 ~ k1052 +020) section bottom width 14.5m, the maximum edge slope height of 33m, is the largest excavation line of section, cutting rock for the Middle Proterozoic dolomite chert bands, joints crack development, with loose soft interlayer, on the slope stability is very negative. The point is close to National Road Blasters ** line, line on the right side dense villages, the construction environment is complex and demanding control of blasting, combined with concentrated quantities, construction period, construction of an easy task.
2, blasting program
Road cutting slope design rate from top to bottom as 1:1,1:0.75,1:0.5, each 10m wide and 2m height of the steps to set the House of Recollected Fragments Taiwan. According to engineering characteristics, combined with the progress of requests and the allocation of resources and other factors, the steps taken by a high degree of multi-layered sub-excavation work surface while the construction plan, construction of deep-hole Blasting by first cutting the main channel pull channel, on both sides Slope reserved 1m ~ 2m wide rock does not burst, as the central body of the main blast walls to reduce the large explosion on the slope of the injury, while reserve of rock blasting, you can burst under the main body blasting conditions and rock properties to more accurately select the blasting parameters and improving the slope of the light burst effect.
2 • 1 Main parameters of controlled blasting blasting area
Vertical drilling with hole drill, drill diameter d = 100mm, drill hole shown in Figure 1.