Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Specific implementations of the present invention are described in detail below with reference to specific embodiments.
As shown in fig. 4, the tunnel surrounding rock excavation construction method provided for the embodiment of the present invention includes:
the method comprises the following steps: construction preparation, namely performing standardized measurement on a construction site;
step two: advanced geological forecast, detecting the un-excavated part of the tunnel by adopting a form of combining geological sketch and geological radar, acquiring a geological sketch map and geological forecast, and judging the safety level through the geological sketch map and the geological forecast;
step three: excavating the tunnel, namely performing three-step construction excavation on the working face of the loess tunnel by adopting a milling and excavating machine, and performing deformation measurement and geological sketch work in real time;
step four: the intelligent monitoring of surrounding rock deformation adopts the mode that three-dimensional laser scanner and infrared thermal imager combine real-time, all-round acquisition space structure data, carries out tunnel deformation analysis, and automatic acquisition tunnel state accomplishes abnormal condition and reports to the police, ensures constructor personal safety.
Step five: and (5) supporting the surrounding rock weak area.
In one example of the invention, preparation is carried out before construction, the end face of construction needs to be measured according to construction requirements, detection data is designed into a construction scheme, a tunnel non-excavation part is detected through geological sketch and a geological radar, the geological sketch obtains a geological sketch map, the geological radar carries out lithology evaluation and geological forecast, and the safety level is judged through the geological sketch map and the geological forecast; the safety level is in the operating range, excavates the tunnel, and the hole body excavation adopts the three-step fractional excavation method to be under construction, cooperates 3 dump trucks and 1 to load and carries out the operation of slagging tap in step. The method comprises the steps of excavating the upper step in a subsection mode, trimming in a subsection mode, moving the machine to the middle step after excavation is finished, carrying out deformation measurement and geological sketch work on the upper step by a monitoring measurement group, moving the machine to the lower step after middle excavation is finished, carrying out deformation measurement and geological sketch work on the middle step by the monitoring measurement group, determining that surrounding rock on the tunnel face is stable and deformation data are normal after monitoring measurement data are processed after excavation of the lower step, and then carrying out primary supporting operation on the upper step, the middle step and the lower step.
The clearance width of the maximum span of the tunnel is 13.25m, the maximum height of a positioning cutting range of the ER1500 milling and excavating machine is 6.78m, the maximum width is 7.43m, the machine needs to be moved once in the excavation process, and the milling and excavating machine is determined to perform excavation operation according to the following method after the process summary of the first stage.
The construction sequence is as follows: adopting three-step excavation, wherein the three-step excavation comprises an upper step 1, a middle step 2 and a lower step 3; excavation of core soil of an upper step 1 → outline trimming of the upper step 1 → moving of a heading machine to the right side of a middle step 2 → excavation of the right side of the middle step 2 → outline trimming of the right side of the middle step 2 → moving of the heading machine to the left side of the middle step 2 → excavation of the left side of the middle step 2 → outline trimming of the left side of the middle step 2 → excavation of a lower step 3 → excavation of the right side of the lower step 3 → outline trimming of the right side of the lower step 3 → excavation of the left side of the lower step 3 → outline trimming of the left side of the lower step 3. Cutting generally requires: and cutting by utilizing the cutting head to vertically and horizontally move to cut out a preliminary section shape, and performing secondary correction when the cut section is inconsistent with the actually required section. The cutting first step is not more than 1 time of the length of the drill bit, and after the cutting range is cut, the heading machine cuts the cutting range of the second step forward. The cutting route is carried out by using a method of cutting from the lower part to the upper part and from the left to the right. The construction safety footage is carried out, according to the construction footage parameters adopted by the test section and the deformation condition of surrounding rocks of the tunnel face, the excavation footage is 2.4m, the surrounding rock on the tunnel face is stable, the block falling phenomenon does not exist, the excavation outline is smooth, the monitoring and measuring data is normal, the field data statistics shows that the time for tunneling the upper step is within 2 hours and 15 minutes, the construction from the upper step to the middle step is carried out after the tunneling of the upper step is completed, the time for tunneling the middle step is 1 hour and 30 minutes, the construction from the middle step to the lower step is carried out after the tunneling of the middle step is completed, the construction completion time to the lower step is within 4.5 hours, the working intensity of operators is moderate, the whole completion time for excavating 3m is within 5 hours, the difference of the depth of the tunnel and the tunneling is 0.5 hour, the footage parameter determined by the process summary of the test section is 2.4 m-3 m, and reasonable dynamic adjustment is carried out according to the surrounding rock conditions, the monitoring and measuring data and the like in the process.
As a preferred embodiment of the present invention, geological sketch: the tunnel working team technicians finish geological sketch work according to related requirements, and the geological sketch work is carried out within a specified time after the tunnel face is excavated, wherein the specified time is 1-3 hours, 2 hours are taken as the optimal time, and the geological sketch has main contents; lithology description, wherein the lithology description comprises rock weathering degree, interlayer combination degree, rock structural surface state and the like; the method comprises the following steps of describing the characteristics of folds, faults, joint fractures, rock stratum occurrence and the like, judging the integrity degree of a rock body according to the position, occurrence, property, width of a fracture zone, material composition, water content and relation with a tunnel; the method comprises the following steps of (1) recording stability characteristics and supporting conditions of surrounding rocks of a tunnel under different engineering geology and hydrogeology conditions, the stability and supporting mode of the surrounding rocks of the tunnel and the deformation condition after primary supporting, analyzing and describing reasons, processes, results and the like of the instability or deformation of the surrounding rocks in detail in a section with the instability or deformation of the surrounding rocks increased; grading surrounding rocks for tunnel construction; collecting the image data of the observation surface.
As a preferred embodiment of the present invention, a geological radar: the LID type ground penetrating radar is adopted for carrying out tunnel cross section layered detection, three steps are adopted for excavation, so that the geological radar adopts single-layer detection, and the single forecasting distance is 30-50 m. Because the geological radar forecasting distance is short, the project department needs to contact a third party in time to forecast the geology according to the construction condition of the face, the forecasting is timely and uninterrupted, and the construction safety is ensured. The geological radar survey line is arranged as shown in figure 1;
as shown in fig. 2, as a preferred embodiment of the present invention, a three-dimensional laser scanner 15 is used to scan the inside of the tunnel. The spatial structure data are accurately and comprehensively acquired in real time, the tunnel deformation analysis is carried out, and the tunnel information construction is guided, so that the risk early warning and forecasting can be timely carried out on the tunnel construction. The inside of the tunnel is scanned in a segmented mode in the scanning process, and a wireless transmission device 13 carried by a three-dimensional laser scanner 15 transmits a real-time scanning picture to a main control module to remotely acquire point cloud data; and after the cloud data are obtained, the main control module processes the data and automatically generates a tunnel structure diagram. In addition, the measured point cloud data are respectively in mutually independent coordinate systems with the measuring stations as the origin, so that the point cloud data of the measuring stations need to be spliced when the tunnel deformation analysis is carried out. And comparing the generated tunnel section diagram with a design specification, observing whether displacement such as peripheral displacement and vault subsidence of the tunnel is in a normal state, and when abnormal conditions such as a recurved point and the like occur in the measured data convergence rate, indicating that abnormal deformation occurs in the surrounding rock and needing to take a reinforcing support measure.
The three-dimensional laser scanner 15 and the infrared thermal imager 14 are installed on the same walking platform 12, and universal wheels or a forward driving device can be installed at the bottom of the walking platform 12 to facilitate movement. The infrared thermal imager 14 and the three-dimensional laser scanner 15 simultaneously monitor the inside of the tunnel. The thermal infrared imager 14 is composed of an infrared detector, an optical imaging objective lens and an optical machine scanning system, and is mainly used for receiving an infrared radiation energy distribution diagram of each position in a tunnel, converting infrared radiation energy into an electric signal by the detector, and displaying an infrared thermal image through a display module after amplification processing and conversion or standard video signals. The display module can be a television screen or a monitor; the infrared thermal imaging camera 14 also utilizes the equipped wireless transmission device 12 to transmit the tunnel construction environment. This facilitates monitoring of abnormal infrared radiation (e.g. water inrush) within the tunnel. The real-time scanning picture and the infrared radiation energy distribution map are matched and analyzed to perform form and energy complementary analysis, so that the detection capability is improved, and real-time and omnibearing detection can be realized.
As a preferred embodiment of the invention, the danger avoiding channel in the tunnel adopts the polymer escape pipe 6, and the polymer escape pipe 6 has the comprehensive properties of light weight, good pipeline toughness, high impact strength, good pressure resistance, difficult deformation, reusability and the like, thereby providing extremely safe and reliable guarantee for the escape and emergency rescue in tunnel construction.
As shown in fig. 3, as a preferred embodiment of the present invention, the support:
aiming at the characteristic that the loess tunnel is easy to seep water, the glass fiber anchor rod 4 is adopted for primary tunnel support to reinforce the surrounding rock, so that the corrosion caused by oxidation reaction of the moisture in the loess and the anchor rod is prevented, and on the other hand, the glass fiber material is very suitable for supporting the surrounding rock of the loess tunnel due to the excellent anti-drawing performance of the glass fiber material.
Aiming at the waterproof treatment of the loess tunnel, a polyurea spraying mode is adopted, the coating can be quickly cured, is compact and flexible, is rich in elasticity and high strength, has excellent anti-seismic performance, and is brushed for 2-3mm at a time. Optimally 2.5 mm.
As another preferred embodiment of the invention, spraying dust-settling equipment is arranged at the vault of the tunnel for dust-settling operation, and when large dust in the tunnel caused by mechanical construction is carried out, spraying dust-settling is carried out timely, so that the dust content of air in the tunnel is reduced. In addition, when the earthwork transportation operation is carried out in the tunnel, the diesel oil transportation device is changed into the electric transportation device, so that the exhaust emission of motor vehicles in the tunnel can be reduced or eliminated. The tunnel shaft 10, the soil storage yard, the sand and stone yard and the stirring system are all managed in a color steel shed closed mode, so that noise and dust are effectively isolated;
in a preferred embodiment of the present invention, the tunnel lighting is a light guide lighting system, which can be connected to the opening or the tunnel shaft 10 to transmit the external natural light to the inside of the tunnel through nondestructive transmission. The light guide illumination system comprises a light guide system lighting means 7 and a light guide system diffusing means 8, and the light guide system lighting means absorbs light energy and transmits the light energy to the light guide system diffusing means 8 for diffuse reflection, thereby performing illumination. The light tube lighting system does not need to be provided with electric equipment and electric wires, so that the daytime electric power lighting cost is saved, and the lighting time can reach about 10 hours per day on average. The method has the advantages of one-time investment, short recovery period, long service life of the system, no operation cost and no maintenance, and can reduce manpower and material resources of common lamps. In addition, the light guide lighting system is externally connected with a photovoltaic cell and connected with a lighting lamp, so that the interior of the tunnel can be sufficiently illuminated at night. After the tunnel is completed, the light guide system can still be continuously operated and used.
As a preferred embodiment of the invention, the tunnel ventilation device adopts an SDS series tunnel jet fan 11, the SDS series tunnel jet fan 11 is communicated with the ventilation pipe 5, and the air in the tunnel is pushed to move along the jet direction by utilizing high-speed jet airflow generated by the jet fan, so that ventilation and air exchange are realized, and the fan has the characteristics of low noise, corrosion resistance, high temperature resistance and the like.
The embodiment of the invention provides a tunnel surrounding rock excavation construction method, which comprises the steps of detecting an unearthed part of a tunnel through geological sketch and a geological radar, obtaining a geological sketch through the geological sketch, carrying out lithology evaluation and geological forecast through the geological radar, and judging the safety level through the geological sketch and the geological forecast; the real-time scanning picture and the infrared radiation energy distribution map are matched and analyzed to perform form and energy complementary analysis, so that the detection capability is improved, and real-time and omnibearing detection can be realized.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.