theoretical basis
1. Foundation treatment
The equipment foundation surface shall be cleaned and free from debris, laitance, dust, oil stain, release agent and other sundries. The equipment foundation surface shall be fully wetted 24 hours before grouting. The accumulated water shall be sucked up 1h before grouting.
2. Determine grouting method
According to the actual situation of the equipment base, select the corresponding grouting method. Because CGM has good flow performance, in general, "self weight grouting" can be used, that is, the slurry is poured directly from the formwork mouth, and it is completely dependent on the self weight of the slurry to flow and fill the entire grouting space; If the grouting area is large, the structure is particularly complex, or the space is small and far away, "high funnel grouting" or "pressure grouting" can be used for grouting to ensure that the grout can fully fill all corners.
3. Formwork erection
The formwork shall be erected according to the determined grouting method and grouting construction drawing. The positioning elevation of the formwork shall be at least 50mm higher than the upper surface of the equipment base. The formwork shall be erected tightly and firmly to prevent loosening and grout leakage.
4. Mixing of grouting material
The amount of water added shall be determined according to the water material ratio recommended on the product certificate. Drinking water shall be used as mixing water, and the water temperature shall be 5~40 ℃. Mechanical or manual mixing can be used. When mechanical mixing is used, the mixing time is generally 1~2 minutes. When manual mixing is used, it is advisable to add 2/3 of the water consumption for mixing for 2 minutes, and then add the remaining water consumption to continue mixing until uniform.
grouting
The grouting construction shall meet the following requirements:
1) Grout shall be poured in from one side until the other side overflows, so as to facilitate the discharge of air between the equipment base and the concrete foundation, so as to fill the grouting. Grouting shall not be carried out from four sides at the same time.
2) After grouting, it shall be carried out continuously without interruption, and the grouting time shall be shortened as far as possible.
3) It is not suitable to vibrate during grouting. If necessary, bamboo slats can be used for pulling and guiding.
4) The thickness of each grouting layer should not exceed 100mm.
5) The grouting of long equipment or track foundation shall be carried out in sections. The length of each section should be 7m.
6) If bleeding is found on the surface during grouting, a small amount of CGM dry material can be spread to absorb water.
7) When grouting large volume equipment foundation with grouting layer thickness greater than 1000mm, 0.5mm stones can be added at a total ratio of 1:1 when mixing grouting materials, but it needs to be tested to determine whether its groutability can meet the requirements.
8) After grouting of equipment foundation, the parts to be removed shall be treated before final setting of grouting layer.
9) During grouting construction and before demoulding, the grouting layer shall be prevented from vibration and collision, so as not to damage the unconsolidated grouting layer.
10) The horizontal distance between the formwork and the equipment base shall be controlled at about 100mm to facilitate the grouting construction.
11) In case of grout leakage during grouting, it shall be handled in time.
12) When the amount of equipment foundation grouting is large, mechanical mixing shall be used for grouting construction.
Secondary grouting of equipment foundation:
(1) Before grouting, the equipment baseplate and concrete foundation surface in contact with grouting materials shall be cleaned, and there shall be no loose gravel, laitance, floating ash, oil stain, wax, etc. The foundation concrete surface shall be fully wetted 24 hours before grouting, and the accumulated water shall be removed 1 hour before grouting.
(2) During secondary grouting, grouting shall be carried out from one side until it overflows from the other side, and grouting shall not be carried out from the opposite sides at the same time. After grouting, it shall be carried out continuously and the grouting time shall be shortened as far as possible.
(3) If the track foundation or grouting distance is long, the construction can be carried out in sections according to the actual engineering situation, and the length of each section shall not exceed 5 meters. If the equipment base plate has a complex structure, pressure grouting should be used.
(4) Vibration is strictly prohibited during grouting. If necessary, grouting booster can be used to push grouting materials along the bottom of the flow direction of the grout. It is strictly prohibited to push grouting materials from the middle and upper parts of the grouting layer.
(5) After the equipment foundation grouting is completed, it is better to
What is ultra-fine cement grouting material
Ultra fine cement grouting material is a new generation of inorganic rigid ultra fine grouting material refined by special equipment from high-strength ultra fine cement, expansion agent, slag and other additives. It is mainly used to fill narrow space structures, and is a branch of cement-based grouting material.
What is the meaning of superfine cement 1250 mesh
It refers to the fineness of cement. The higher the mesh, the finer the cement. For example, 800 mesh cement is finer than 1250 mesh cement.
The significance of pipe shed grouting:
1. As an important auxiliary construction method in tunnel construction, pipe shed and pre grouting reinforcement have played a significant role in preventing tunnel collapse, controlling ground subsidence, and inhibiting ground displacement.
2. The pipe shed construction technology plays a supporting role to enhance the construction safety and improve the long-term stability of the tunnel, which has significant economic and social benefits. At the same time, excavation under pipe shed support can reduce and prevent surrounding rock collapse.
3. Key points for grouting construction of tunnel pipe shed.
Key points of construction control
1. Before drilling, measure the plane position, inclination and external angle of the hole, and number each hole.
2. The external angle of drilling shall be 1 °~3 °, and the construction site shall be adjusted according to the actual situation. The determination of the elevation angle of the drill hole shall be determined according to the drilling depth and drill pipe strength, which is generally controlled at 1 °~1.5 °. During the construction, the drilling rig subsidence and left and right offset shall be strictly controlled.
3. The drilling plane position shall be strictly controlled, the pipe shed shall not intrude into the tunnel excavation line, and adjacent steel pipes shall not collide with each other and cross.
4. The inclination of the hole shall be measured frequently, and if the error is found to be out of limit, it shall be corrected in time. If the final hole is still out of limit, the hole shall be sealed and re drilled in situ.
5. Master the pressure and speed of spud in and normal drilling to prevent rod breakage.
The composition of epoxy resin grout is different from that of cement-based grout
In terms of composition, epoxy resin grouting material is a three component grouting material, which is composed of material A (epoxy resin), material B (curing agent) and material C (filler). Cementitious grouting material is a kind of powder material prepared by using single component cement as binder, adding aggregate, supplemented by micro expansion, anti segregation and other substances. Due to the different substances contained in the two, the use methods of the two are also different. When used on the site, the epoxy resin grout is first mixed with one barrel of material A and one barrel of material B into the container, and then mixed evenly. Then, six bags of material C are added while mixing (the specific amount can be adjusted according to the site environment), and mixed evenly manually or by machine. For cement-based grouting materials, according to the site conditions and water adding instructions, add appropriate amount of water and mix evenly before use.
The function of epoxy resin grouting material is different from that of cement-based grouting material
Epoxy resin grouting material can meet the requirements of heavy load grouting, such as track foundation, bridge support and other areas under strong pressure grouting; It is more suitable for the installation of high vibration equipment and heavy equipment, such as secondary grouting of steel rolling mill, plate mill, rod mill, punch, grinder, ball mill and other equipment; It is suitable for grouting in equipment foundation areas susceptible to chemical attack, such as grouting of pumps and motor equipment in paper making and chemical industries; It is suitable for equipment foundation grouting in corrosive media environment, such as equipment grouting in acid, alkali, salt and other media. The cement-based grouting material is suitable for grouting and fixation, such as equipment foundation, anchor bolt anchorage and grouting and fixation of rebar planting; It is applicable to reinforcement works, such as beam and column section enlargement reinforcement works; It is suitable for repairing projects, beams, slabs, columns, foundations, floors of building structures, etc. As can be seen from the above, the functions of the two are different, and the materials should be selected according to the specific needs.
Construction steps
1. Prepare mixing machines, grouting equipment, formwork and curing materials, clear the grouting space and wet the concrete surface in advance.
2. The formwork shall be erected and the joints of formwork shall be sealed with cement (sand) slurry and plastic tape to ensure no water or slurry leakage.
3. Add water according to 12-14% of the weight of grouting material (mechanical mixing for 2-3 minutes, manual mixing for more than 5 minutes)
4. Pour the evenly mixed grouting material into the grouting part from one direction. If necessary, bamboo strips or steel chisels can be used for diversion, and the formwork can be properly vibrated or gently knocked.
5. After construction, it shall be covered with plastic film and covered with straw curtain or cotton quilt for wet curing for 3-7 days.
6. The operating temperature is - 10 ℃ to 40 ℃. It is strictly prohibited to add any admixture or additive into the grouting material.
