As a graduate of Civil Engineering, the formulas and diagrams in textbooks suddenly came to life the moment I stepped onto a real construction site. With a hazy understanding of foundation reinforcement technology from classroom studies, I followed the project team to the construction site. The ravine-riddled terrain here features complex geological conditions of 38-40-meter deep-seated landslides, resembling a natural practical classroom waiting for me to unlock the codes of ground reinforcement with professional knowledge. As the commuter vehicle rumbled along the winding mountain road, the spectacular silhouette of hammer arms standing tall on the distant construction site came into view, officially kicking off a journey that tests engineering craftsmanship and technical practice.

At the beginning of the construction site, the towering compactor pointed straight at the sky, and the piled up stone materials were neatly arranged. The unique charm of SDDC (deep dynamic compaction method inside the hole) technology was overwhelming. The project manager metaphorically describes SDDC as a deep therapy for the earth, using deep replacement of soft foundation soil and compacting with crushed stone filling to make the foundation penetrate deep into the sliding bed and form piles, which are used to support the landslide body, stabilize the slope, and reshape the earth's tendons. ”At the technical briefing, I systematically learned the core mystery of this technology - a specially designed 5-15 ton column hammer falls freely from a high altitude and carries out high-energy ramming in the hole with thunderous force. Through the triple action of "displacement compaction consolidation", the loose flowing sliding foundation is improved into a composite foundation. Compared with traditional dynamic compaction, SDDC adopts an innovative process of layered filling inside the hole, which is like customizing a "reinforcement armor" for the foundation, accurately controlling the reinforcement depth and compactness, and is particularly adept at tackling complex geological problems such as deep soft foundation soil and miscellaneous fill soil.

The drilling process can be regarded as the "geological game field" of the construction site. When the mechanical drilling reaches a depth of 5-10 meters underground, the drill bit suddenly encounters a hard rock layer, and the drilling speed drops sharply from the original 0.5 meters per minute to almost stagnant. The continuous operation for half an hour only advances a few centimeters. In the face of this sudden situation, the project team quickly organized multiple personnel to consult and finalize the combination plan of "rotary drilling and long spiral drilling": first use a rotary drilling rig to pre crush the rock area, and then use a long spiral drilling rig to complete precise drilling. This intelligent solution not only greatly improved construction efficiency, but also made me deeply understand that excellent construction plans are never fixed templates, but dynamic strategies that need to be flexibly adjusted according to geological changes.

The most shocking thing is undoubtedly the compaction and filling operation site. With a deafening roar, a 10 ton heavy hammer fell vertically from a height of 10 meters, and the enormous impact made the ground tremble for several meters around. I held a measuring instrument in hand and witnessed the wonderful changes in the pile during the compaction process - in the first few rounds of compaction, the single settlement could reach 20 centimeters, and the loess and filling materials gradually compacted under the repeated hammering of heavy hammers; As the number of impacts increases, the settlement gradually narrows and eventually stabilizes within 5 centimeters. The quality red line repeatedly emphasized by the project manager is still in our ears: "The average settlement of the last three strikes must be controlled within 50 millimeters, which is the lifeline to ensure the compactness of the pile." Every data record carries the ultimate pursuit of quality by the engineering personnel.

This internship experience, accompanied by heavy hammers, loess, and data, has become the most precious gift of my career growth. In the day and night baptism of the pounding sound, I not only found professional codes that were not answered in textbooks such as "why the pounding energy needs to be adjusted according to the soil" and "how to accurately judge the compactness through the pounding settlement", but also gained a deeper understanding of the responsibility and commitment of engineering personnel. The direct construction of SDDC is related to the safety of the foundation, and there is no room for any luck or slackness. This kind of awe, like walking on thin ice, always reminds me to maintain a rigorous and meticulous work attitude. Looking back now, the dawn and dusk of recording data on the construction site, and the moments of overcoming difficulties with the team, have already become the cornerstone of my professional growth, guiding me to move forward firmly in the field of civil engineering.

Zhangbin