Question 2: What is consolidation grouting? Consolidation grouting refers to injecting cement slurry into broken or discontinuous rock mass to form a whole, which increases various mechanical indexes and impermeability of rock.
Question 3: What is the purpose and function of consolidation grouting for dam foundation? Enhance the integrity of dam foundation, namely: ① improve the integrity and homogeneity of rock; ② Improve the compressive strength and elastic modulus of rocks; ③ Reduce the deformation and uneven settlement of rocks.
Question 4: Other grouting methods for consolidation grouting 1. 1 There are two grouting methods for consolidation grouting: circular grouting and pure pressure grouting, and the grouting construction technology is basically the same as curtain grouting. 1.2 grouting technology requires grouting holes to be constructed according to the principle of sequential encryption, which can be divided into two-sequence construction or three-sequence construction. Each hole should be drilled in sections from top to bottom, grouted in sections or grouted after drilling the last hole. When the bedrock section of the grouting hole is less than 6m, the whole hole grouting can be completed at one time. When the geological conditions are not good or there are special requirements, grouting can be carried out in sections. For projects with grouting pressure not greater than 3MPa, grouting holes should be grouted in sections. Grouting holes should be washed with pressurized water until the backwater is clean. The flushing pressure can be 80% of the grouting pressure, which is greater than 1MPa, so 1MPa should be adopted. The water pressure test before grouting in grouting hole should be carried out after fissure flushing, and the single point method should be adopted. The number of test holes shall not be less than 5% of the total number of holes. Under the principle of not lifting the foundation rock mass and the concrete of the bearing platform, the consolidation grouting pressure should be increased as much as possible. Under the specified pressure, when the injection rate is not more than 0.4L/min, grouting can be completed for 30 minutes. The water pressure test, rock mass wave velocity test and static elastic modulus test of consolidation grouting quality should be carried out 3~7d, 14d and 28d after grouting. The water pressure test of grouting quality shows that the qualified rate of hole section should be above 80%, and the water seepage of unqualified hole section should not exceed 50% of the design value, and it is not concentrated. The sealing method of grouting hole should be mechanical grouting or pressure grouting. 1.3 When the rock geological conditions are complicated, generally, the field consolidation grouting test is carried out first to determine the technical parameters (hole spacing, row spacing, hole depth, hole arrangement form, grouting sequence, pressure, etc. ). Shallow consolidation grouting holes are mostly drilled by pneumatic drill; Deep holes are usually drilled with DTH drill or hollow drill. Plane holes are arranged in plum blossom, square and hexagon. Row spacing and final hole spacing are generally 3 ~ 6m, and drilling and grouting shall be carried out according to the gradual compaction method. Grouting material is mainly cement slurry. In the area where rock joints and cracks are developed, when the amount of mud is large, cement mortar is often used instead. When grouting, it starts from the slurry and gradually thickens until it reaches the end standard. After grouting is completed, the inspection methods of consolidation effect are as follows: ① drilling inspection holes for water pressure test and core sample inspection; ② Measurement of elastic wave velocity and elastic modulus; (3) When necessary, excavate flat holes or shafts for visual inspection.
Question 5: What is the difference between consolidation, curtain and filling grouting? 5 points 1. grouting material
Consolidation grouting and curtain grouting are filled with cement slurry, and the specification stipulates that the concrete strength grade is not lower than No.425, and the filling grouting is filled with mud or cement clay slurry;
2. Grouting pressure
Consolidation grouting and curtain grouting belong to medium pressure grouting, and the grouting pressure is slightly higher, while filling grouting belongs to low pressure grouting, and the pressure is generally less than 0. 1Mpa (split grouting is not limited by this);
3. The purpose of consolidation grouting is to improve the overall stability of bedrock and enhance the mechanical strength of rock, and the irrigation body is generally bedrock; The purpose of curtain grouting: bedrock is impervious (forming impervious curtain), and the irrigation body is generally bedrock; The purpose of filling grouting: dam and dike are impervious, and the irrigation body is generally soil or gravel layer (fine sand and quicksand cannot be injected).
In addition, you can refer to:
Technical specification for earth dam grouting (SD266-88)
Technical Specification for Cement Grouting Construction of Hydraulic Structures (SL62-94)
My knowledge is limited, and that's all I know. I hope I can help you.
Question 6: Can consolidation grouting be done without water pressure? Consolidation grouting is a kind of rock fracture grouting, which does not need to produce curtain area, so it is not necessary to press all holes, but at least it is 5% of the total number of holes. According to the situation of rock seepage and slurry eating, water pressure test holes can be added appropriately.
Question 7: What does grouting cement mean? Ultra-fine cement is made from portland cement by special process, which makes its specific surface area reach 400-800 m2/kg. It has the characteristics of fine fineness, high early strength, strong adaptability of additives and good fluidity of slurry. It is suitable for grouting of voids and cracks in mass concrete and rocks.