二、施工过程中应注意事项和具体施工方法在施工工程中，常常由于某个环节的

Second, the construction process should be careful and specific construction methods <br>in construction projects, often due to the negligence of a link, which led to the entire construction process fall short, it should be done in the construction bold but cautious, avoid mistakes, and to master the basic construction methods, in order to ensure the safety of construction at the same time, to ensure construction quality. <br>1, strict testing quality construction materials. The selection of construction materials, to fully meet the design requirements of the standard, even the strength and quality to be completely out quality standards required for construction. Mainly in the selection strand, to use relevant qualification certificate or proof of the quality strand credentials, strictly eliminate the material is not up to the standard of the construction site. First, the choice of material from the material appearance, no exterior damage is the most basic, while serious distortions corrosion and deformation does not meet construction requirements. Followed by technical indicators, quality must meet the relevant provisions Strand regulations and even exceed the current GB5224-85 standard, technology standard 186Mpa meet quality requirements, after testing the mechanical properties can meet construction standards. <br>2, in strict accordance with the technical requirements of construction. When cutting strand, cutting the strand to use special equipment, to ensure that the cutout before cutting two banding firmly avoided during the cutting operation, the loose strands Beng wounding, when knitting strand bundle, strictly Numerical beam according to the specific requirements of knitting, a good measurement of the pitch segment, in accordance with the requirements of design drawings compiled sequentially numbered bundle. For diameter and mass of the bellows construction to meet the design requirements, or in material handling during construction to prevent the bellows welding sparks to reach the tendon or strand surface, while the metal sleeve and the anchor pad to the first beam vertical angle and holding the tendon.<br>3, in accordance with the overall construction program construction methods. In strict accordance with the construction program, methodical, step by step according to the actual situation of the construction site, take a scientific construction methods, construction schedule co-ordination arrangements. Construction methods are commonly used drilling, wear beam Tongjiao irrigation, tensioning and grouting pipe and the like. Need to produce a substantially pore-location map, network installation positioning, mounting the bellows, the exhaust hole provided in several steps. Tongjiao beam through irrigation and the vibrator to be noted that the construction of the proper use of method of operation, to avoid the impact of the vibrator and bellows. Pay attention to concrete strength and symmetrical force tension, the tension and the beginning of a good grasp of the power of control. Quality Requirements To strand elongation and calculated errors are less than 6%, the wire is not broken more than one beam. 5cm outer retaining anchor strand, and cut off the excess portion of the encapsulation with cement. Grouting construction in the pipeline, in addition to strictly control the tension end time, the water-cement ratio of cement grouting must be strictly controlled. While ensuring that the anchor only closed when the door underflow slurry, the slurry into the bore of the valve, so that pressure reaches 0.6--0.7Mpa, and after 2 minutes in the bottom can be closed without leaking.

Second, the construction process should be precautions and specific construction methods<br>In the construction project, often due to the negligence of a link, resulting in the entire construction process, so should be bold in the construction, to avoid mistakes, at the same time to master the basic construction methods, in order to ensure safe and orderly construction at the same time, to ensure the quality of the first construction of the project.<br>1, strict inspection of the quality of construction materials. In the selection of construction materials, to fully meet the design requirements, and even strength and quality to completely exceed the quality standards required for construction. Mainly in the selection of steel strands, to choose the relevant qualifications or quality proof of the steel strands, strictly put an end to materials not up to the standard into the construction site. First of all, the selection of materials from the appearance of the material, no appearance damage is the most basic, at the same time serious corrosion distortion deformation and other conditions also do not meet the construction requirements. Secondly, on the technical indicators, the steel stranding sleb sitmusts that the quality must meet or even exceed the relevant provisions of the current GB5224-85 standard, and meet the requirements of 186Mpa's quality technical conditions, which can meet the construction standards after the inspection of mechanical properties.<br>2, in strict accordance with the technical requirements of the construction. In cutting steel strands, to use special steel strand cutting equipment, before cutting to ensure that the cut two sections tied firmly, to avoid cutting work process, the stranding loose pick-up injuring people, steel stranding, to strictly in accordance with the requirements of the formation, measure the specific value of the segment spacing, in accordance with the design drawing order requirements of the beam number. The diameter and quality of the bellows pipe used for construction should meet the design requirements, in the handling material or construction process, to effectively prevent welding sparks from touching the bellows or steel strands of steel bundle surface, while the metal casing and beam head anchor pad to maintain the vertical angle with the steel bundle.<br>3, in accordance with the construction procedures to coordinate the construction methods. In strict accordance with the construction procedures, in a methodical and systematic manner according to the actual situation of the construction site, the adoption of scientific construction methods, overall arrangements for the progress of construction. Common construction methods are perforation, beam perforation, watering, pulling and pipe pulp. Holes generally need to make positioning maps, installation of positioning networks, installation of bellows, vents several steps. In the construction of beam and watering, we should pay attention to the correct operation method of vibrator, so as to avoid the impact of vibrator and bellows. When pulling, pay attention to the strength and symmetrical exertion, grasp the initial pull and force control. The quality requires that the steel strand elongation value and the calculation value error should be controlled within 6%, and the wire broken beam should not exceed 1. In addition to retaining 5cm, the excess part is cut off and sealed with cement. In the pipeline pulp construction, in addition to strictly control the end time of Zhangla, the pressure pulp cement water ash than control is more stringent. At the same time to ensure that the anchor out of the pulp door out of the thick pulp can be closed, the hole into the pulp valve, to ensure that the pressure reaches 0.6 -0.7Mpa, and lasts 2 minutes in the absence of leakage can be closed.

II. Precautions and specific construction methods during construction<br>In the construction project, the whole construction process is often short of success due to the negligence of a certain link, so we should be bold and careful in the construction to avoid mistakes, at the same time, we should master the basic construction methods, while ensuring the safe and orderly construction, and ensure the construction quality of the project.<br>1. Strictly inspect the quality of construction materials. The selection of construction materials shall fully meet the design requirements, and even the strength and quality shall completely exceed the quality standards required for construction. Mainly in the selection of steel strand, it is necessary to select the steel strand with relevant qualification certificate or quality certificate, and strictly prevent the materials that do not meet the standard from entering the construction site. First of all, from the perspective of material appearance, no appearance damage is the most basic, and serious corrosion, distortion, deformation and other conditions do not meet the construction requirements. Secondly, in terms of technical indicators, the specified quality of steel strand must meet or even exceed the relevant provisions of the current gb5224-85 standard, meet the requirements of 186mpa quality technical conditions standard, and meet the construction standard after the inspection of mechanical properties.<br>2. Construction shall be carried out in strict accordance with technical process requirements. When cutting the steel strand, special steel strand cutting equipment shall be used. Before cutting, two sections of the cut shall be bound firmly to avoid injury caused by loose strand during cutting operation. When binding the steel strand, the specific value of section spacing shall be measured in strict accordance with the binding requirements, and the bundle number shall be numbered in accordance with the sequence requirements of the design drawings. The diameter and quality of bellows used for construction shall meet the design requirements. In the process of material handling or construction, it is necessary to effectively prevent electric welding sparks from touching the surface of bellows or steel strand steel strand. Meanwhile, the metal sleeve and beam head anchor pad shall maintain the vertical angle with the steel strand.<br>3. Coordinate the construction method according to the construction procedure. In strict accordance with the construction procedures, according to the actual situation of the construction site in an orderly and step-by-step manner, scientific construction methods shall be adopted and the construction progress shall be arranged as a whole. The commonly used construction methods are hole making, bunching, concrete pouring, tensioning and pipe grouting. To make a hole, it is necessary to make a positioning diagram, install a positioning net, install a bellows and set an exhaust hole. In the construction of bunching and concrete pouring, attention should be paid to the correct operation method of vibrator to avoid the impact of vibrator and bellows. When tensioning, pay attention to the concrete strength and symmetrical force application, and grasp the initial tensioning and force control. According to the quality requirements, the error between the elongation value of steel strand and the calculated value shall be controlled within 6%, and no more than one steel wire strand shall be broken. In addition to retaining 5cm for anchorage of steel strand, the surplus part shall be cut off and sealed with cement. In the pipeline grouting construction, in addition to strictly controlling the end time of tensioning, the water cement ratio of grouting cement should be strictly controlled. At the same time, make sure that the outlet valve of the anchorage can be closed only when the thick slurry is discharged. The pressure of the inlet valve of the duct shall reach 0.6-0.7mpa, and it can be closed after 2 minutes without water leakage.<br>