Standing against the pagoda ruler, carrying the theodolite on the back, climbing mountains and wading with the weight of the full scale instrument, and completing the measurement work of fixed points and lines, the hard work and sweat shed every day are beyond reason for ordinary people. And in the depths of Gaoligong Mountain, where the jungle is stacked, the surveying team that undertakes the task of "navigating" the Gaoligong Mountain Tunnel, the "Asia's longest tunnel" of the Dali (Li) Rui (Li) Railway, walks on the steep mountain tops and deep in the strata. The dangers and hardships experienced are unimaginable to the workers under the conditions of wind and rain.
"If the mountain doesn't stay, we have to go out!"
In July 2015, the entrance of the Gaoligongshan Tunnel excavated from the cliffs of the Nujiang River to Tengchong was accurately located, and the Yunnan-Myanmar Highway, the "National Defense Corridor" of the Anti-Japanese War, was connected, and the construction access road to the construction gate of the Gaoligongshan Tunnel was built as soon as possible. When , the survey work to find the design aerial survey GPS positioning points is carried out simultaneously.
Once, two surveyors, Guo Jiye and Zhai Hui, who were tasked with finding out the location of the wires, climbed up the Songshan Mountain, which was set up by the Japanese army during the Anti-Japanese War, as they scraped away blades of thatch that were as sharp as blades and various vine forests that were so dense that they could hardly squeeze into their bodies. Fortress Heights, when the GPS point was found after all the hard work, the sun had already set. The non-stop rain, like a fermenting agent with a strong catalytic effect, stimulates the unique fog of Gaoligong Mountain, making the dangerous roads in the ravines and jungles that are extremely difficult to walk, showing a kind of strangeness covered by fog.
With the jungle and mountains completely blocking the mobile phone signal, the two of them moved one foot higher and one foot lower, but moved to the depression with a feeling. Wet from the rain all over the body and teeth chattering from the cold, I thought that even if I found a thatched hut in the mountains where the locals watch the crops, I would not want to move on with my legs.
However, gritted your teeth and turned over a few mountain ridges under the conditions of cold and hunger, except for the waves of pines, there are still mountains full of mist. After the two encouraged each other to climb over a ravine, they found a light flickering on the opposite side of the mountain peak far away. Although the light passing through the dense fog gives people a feeling of blinking ghost eyes, but for the exhausted survey team members, this kind of excitement that makes people feel horrible and flickering is no less than Magellan's discovery of the New World of America. .
Seeing that the lights of hope ahead were getting brighter and brighter, the two of them seemed to have forgotten the feeling of exhaustion. Regardless of the various vines blocking the way, they speeded up their pace and finally found a single family under a field ridge. The old woman who was lighting the lamp and cooking dinner, after being told the direction of the country road, no longer cared about the little remaining energy left in her legs that had not been filled with water for most of the day. She gritted her teeth and insisted on moving forward for more than an hour. The pickup truck with the equipment entered the mountain and escaped successfully.
A special "running field" in the tunnel
The Gaoligongshan Tunnel reserved for the expansion and reconstruction of the second line, due to the steepness of the mountain, lost the conditions for opening inclined shafts from each section of the tunnel line, dividing the long-distance tunnel, and realizing long tunnels and short tunnels. Therefore, the excavation mileage of more than 30 kilometers is unshakable at the top of the list of Asian railway tunnels! This puts forward higher requirements for the measurement accuracy that needs to be "navigated" by measurement in each construction step. Just to complete the parallel pilot pit and the main tunnel with a distance of 20 meters for the horizontal tunnel, after the geological rock formation within the design range is hollowed out and penetrated by blasting, a closed loop of measuring wires needs to be completed, which basically requires running continuously for half a day to complete.
The excavation distance is more than 90 meters long. In order to open more working faces, the cross-holes are opened at the corresponding mileage. Special measuring instruments are installed, and infrared rays are used to scan points, and finally the single measurement operation of wire closure is realized. It is divided into 7 bigger. As for the 7 plate measurement areas, 8 surveying stations are derived from each point. Each surveying station is divided into 9 surveying points. Accurate measurement data enables the subsequent follow-up concrete lining of the tunnel to proceed normally without deviation.
The work of placing the instrument and finding the measurement setting-out point on the corresponding side seems simple, but it is necessary to complete this group of measurement items supported by data within a few hours, generally by looking at the measuring instrument and looking at the mirror The survey project completed by the three persons of returning points, piling, and line marking must be completed in a rapid movement to complete 9 measuring return points in a single item of surveying and mapping. It can be said that the 90-meter-long, cross-sectional area of 5 square meters, the Unicom main tunnel and the horizontal tunnel reserved for the second-line parallel road pit, and all the return point items in the 7 major regional plates were taken to form a high-precision closed loop, basically Done while running.
The "special runway" in the depths of the Gaoligong Mountains is a test of will and endurance for young surveyors, and it is also a career examination room. ! What is commendable is that no one of the surveyors was defeated in the face of dangerous rocks, collapses, falling rocks, high temperature, geothermal heat, etc., but with high passion and fighting spirit, they produced accurate measurement data for the more than 30 kilometers long " Asia's Longest Tunnel" was excavated for precise navigation.
The "special warfare" posture of water rushing and electric shock
The horseshoe-shaped Gaoligongshan Tunnel is hollowed out, and there is no time to complete the concrete lining of the empty side walls and the semi-arc top of the arched surface. From time to time, surveyors with electric drills drill holes into the rock formations around the tunnel, and then measure the diameter of the tunnel. The 16 mm rebar is wedged into the drill hole and fixed with mortar. After solidification, observe the static changes between the surrounding rocks after blasting and extract relevant values.
This action of squeezing the handle and pressing the button to drill can be done by ordinary workers. However, at the tunnel excavation site in Gaoligong Mountain, which is humid, hot, and splashed with water, the special working environment makes this simple operation skill extremely meaningful.
Although wearing waterproof rain boots and raincoats, the jets of water sprayed out under pressure were still pouring into the neckline and cuffs at the moment when the drilling team changed angles, replaced the drill bit and wedged the rebar into the mountain. After one shift, the whole body is basically soaked.
The "soaked chicken"-like embarrassment can still be tolerated, and what brings great pressure to the willpower test of the players is the feeling of "intimate" contact with static electricity.
Also wearing special gloves with excellent insulation performance, and wrapping a circle of insulating waterproof tape on the wire interface, and a grounding device to prevent electric shock is installed on the work trolley that can adjust the height and move freely. In misty, water splashing, and humid environment conditions, moist mist and water flow become the best "medium" to connect static electricity. The longer the time, the probability of static electricity "coming out" increases greatly, which makes the drilling team suffer.
The discomfort caused by the static electricity shock to the body, and the "soaked chicken"-like embarrassment all over the body did not reduce the fighting passion of the measurement team members. They are fully armed like "special fighters". In addition to reducing static electricity interference, they arrange a side member next to the special distribution box to push on the switch after all the lines are connected to prevent safety accidents under the power-on state. Create good conditions for the completion of tunnel surrounding rock measurement operations, and while completing special operations with high quality, minimize the discomfort caused by static electricity to the body and improve work efficiency.