What are the advantages of drum cutters in soft rock? How to distinguish soft rock and hard rock?

Writer： admin Time：2022-11-23 15:14:58 Browse：252℃

Excavation by drum cutter is generally used for soft surrounding rock sections with weak soft and stable working ability. Therefore, during the construction process, the specifications of less vibration, strong support, early sealing, and close follow-up of the second lining should be followed.

Immediately after excavation, cement should be used to stabilize the soil-enclosed excavation surface, construct steel arches, and install anchor rods to prevent the excavation surface from being exposed for too long, which will cause the rock layer to be rapidly and strongly weathered and lose the ability to stabilize; The footage should be established according to the self-stability of the excavated surface stone layer, generally 0.5~1.5m, which is the distance between 112 cotton steel arches.

In addition, the construction time of the secondary lining cannot be realized until the initial fulcrum is fully stabilized. The secondary lining structure should be improved, and the construction should be carried out as soon as possible to avoid continuous deformation caused by staying too long after the initial fulcrum.

Generally speaking, the interval of secondary lining is controlled in the middle of 30~50m on the palm surface. Tracking the secondary lining immediately can effectively control the deformation of the initial fulcrum, which is beneficial to the stability of the palm surface.

Rocks with a biaxial saturated state compressive strength exceeding 60 MPa are called "hard solid rocks", those with a compressive strength of 3060 MPa are called "harder solid rocks", and those with a compressive strength lower than 30 MPa are called "soft rocks".

The specification of comprehensive zoning, in addition to being based on the rock strength index, should also take into account the impact of a series of natural factors such as rock formation, rock formations, normal faults, fracture growth and erosion levels.

In the geological research of rocks, due to the poor mechanical strength and reliability of soft rocks, they often become the focus of geological research in rock formations, and hard rocks are softer than hard rocks.

After the excavation of the milling excavator is completed, the milling excavator exits the equipment workbench (it must be regularly maintained and maintained for industrial equipment), and then starts to assemble slag, slag, spray, and anchorage pit projects.

After the spray anchor support is completed, slowly start the next cycle of excavation work.

The speed, actual effect and function of milling are closely related to the geological conditions of milling, the angle, direction and construction sequence of the milling part. According to field data analysis, low tensile strength soft rock (≤10mpa) can excavate 30m3 per hour, and the footage is as short as 0.8~1m.

The section is limited by the steps, the floor space is small, and it can be carried out within 1-2 hours. When encountering abnormally weak and pooly surrounding rocks, due to the poor stability of the surrounding rocks, it is necessary to excavate the stone layer of about 30cm of embedded parts with air picks for human resources.

For the geological structure of quartz sandstone, because the fiber laser cutting drum moves upward, the rock layer cannot be cut by fiber laser, and the work efficiency is very low. Finally, the excavator breaker is used to excavate together with the excavator.

The milling method can be used for weak surrounding rocks and loess plateau sections that cannot be blasted on site or excavated by excavators.

At present, excavators are mainly used in the construction of tunnels in loess layers. However, due to the limitation of excavator grab cranes, when excavating nearby, it is necessary to excavate too much, otherwise the excavation will not be in place.

Milling machines and loaders can solve the limitations of excavating loess tunnel engineering construction by excavators. One excavation is immediate, and no dead ends are left in the next cycle of excavation, which speeds up the construction progress.