During urban engineering construction, loose stratum with scree and gravel has often been encountered and mortar rock bolt is often used. But it is easy to happen hole collapse, difficult to insert and other problems, then casing pipe should be needed, which reduces construction efficiency. On the other hand, slurry will not full and supporting effect is poor. While SDA bolt can overcome problems during installation and grouting of urban loose stratum.
SDA bolt is a kind of hollow bar with continuous thread, one end connects to drill machine and another one connects to one-off drill bit. When drilling, slurry can be injected through hole of bolt, which realizes integrated construction of drilling, grouting and anchoring. After grouting, it can ensure cement mortar and cement paste wrapping overall length of SDA bolt, contacting with surrounding soil body and then forming a combination. When grouting, slurry is from bottom of hole, stop-grouting plug is installed to realize pressure grouting, which can fill gaps in sandy gravel stratum, enlarge diffusion radius and anchoring range. So, SDA bolt has good anchoring effect in loose stratum.
A lot of experience have shown that SDA bolt in loose stratum has safe, reliable and convenient characteristics and can be widely used in urban engineering construction.