On September 3, 2013, Huayuan Successfully Completed the Loushanguan Expressway Crossing Using a 23-to-1 Pipeline Pullback Technique

Loushanguan is located in Loushanguan Town, Zunyi City, Guizhou Province, a historic revolutionary site. The Loushanguan Expressway HDD crossing project had a total length of 810 meters with a pipe specification of Ø406.4 × 8.7 mm.

The project presented significant challenges:

* Steep mountainous terrain and limited space for pipeline prefabrication;

* Complex geology with hard rock, requiring drill bit replacement every 100 meters;

* Uneven distribution of fractures and karst caves, frequently causing loss of drilling fluid circulation;

* Crossing strata consisting of valley backfill gravel layers, where incidents of stuck drill strings and borehole collapse were common.

Through multiple rounds of innovation and process optimization, Huayuan successfully solved the problems of drilling fluid loss caused by karst caves and fractures, and overcame the challenges of stuck drill strings and borehole collapse in backfill gravel layers. Despite extremely limited space for pullback operations, the team adopted a 23-to-1 pipeline pullback method. At 18:58 on September 3, 2013, we successfully crossed under Loushanguan.