1、32 钻孔灌注桩基础3.2 Foundation of bored grouting pile321 施工方法3.2.1 Construction method1 准备场地、测量放线：施工前应进行场地平整，清除杂物，钻机位置处平整夯实，准备场地，同时对施工用水、泥浆池位置，动力供应，砂石料场，拌和机位置，钢筋加工场地，施工便道，做统一的安排。测量放线，根据设计图纸用经纬仪（或全距仪）现场进行桩位精确放样，在桩中心位置钉以木桩，并设护桩，放线后由主管技术人员进行复核，施工中护桩要妥善看管，不得移位和丢失。1. Site preparation, measuring/setting-out: gr
2、ound leveling, sundry removal, the drill machine position leveling and compacting should be carried out before construction in order to prepare site, meanwhile the positions of construction water tank , mud sump, power supply, sand-gravel stockpile, mixer, the steel reinforcement processing field, a
3、nd the construction road should be arranged uniformly.Measuring/setting-out: accurate setting-out of pile position should be carried out on site with the theodolite (range instrument) according to design drawings; a timber pile shall be compacted at the pile center position, where the fender piles s
4、hall be set up. Double-checking shall be carried out by the competent technical personnel after setting-out; the fender piles under construction shall be taken care properly and shall not be shifted and lost.2埋设护筒护筒因考虑多次周转，采用 3-10mm 钢板制成，护筒内径，使用旋转钻机时比桩径大 10-20cm，使用冲击钻时比桩径大 20-30cm，埋置护筒要考虑桩位的地质和水文情况，
5、为保持水头护筒要高出施工水位（或地下水位）1.5m，无水地层护筒宜高出地面 0.3-0.5m，为避免护筒底悬空，造成蹋孔，漏水，漏浆，护筒底应坐在天然的结实的土层上（或夯实的粘土层上） ，护筒四周应回填粘土并夯实，护筒平面位置的偏差应不超 5cm。护筒埋置深度：在无水地区一般为 1-2 倍的护筒直径。在有水地区一般为入土深度与水深的 0.8-1.1 倍（无冲刷之前） 。2. Casting tube burying Considering the turnover for many times, the casting tube is made of 3-10mm steel plate; i
6、ts inside diameter is 10-20cm larger than the pile diameter when using rotary drill and is 20-30cm larger than the pile diameter when using percussion drill; as for the embedment of casting tube, the geological and hydrologic conditions at the pile position shall be considered; in order to maintain
7、that the water head casting tube is 1.5m higher than the construction water level (or underground water level), the casting tube at waterless ground should be 0.3-0.5m above the ground level; in order to avoid hole collapse, water leakage and mud leakage caused by the hanging of casting tube bottom,
8、 the casting tube bottom shall be located on natural and stout soil layer (or on compacted clay layer); space around the casting tube shall be backfilled clay and be compacted, and the deviation of casting tube planimetric position shall not exceed 5cm. The embedded depth of casting tube: generally
9、is 1-2 times of casting tube diameter in waterless areas; generally it is 0.8-1.1 times of the buried depth and water depth in water-bearing areas (before washing out).3. 选择钻孔机械：正循环钻机：粘性土、砂类土、砾、卵石粒径小于 2cm，钻孔直径 80-250cm，孔深 30-100m。反循环钻机：粘性土、砂类土、卵石粒径小于钻杆内径 2/3，钻孔直径80-250cm，孔深泵吸10 的粘性土或膨润土，对不同土层泥浆比重可按下
10、列数据选用：粘性土和亚粘土可以就地造浆，泥浆比重 1.1-1.2 间；粉土和砂土应制备泥浆，泥浆比重 1.5-1.25；砂卵石和流砂层应制备泥浆，泥浆比重 1.3-1.5。4. For preparation of mud, the cohesive soil or bentonite with plasticity index Ip10 shall be selected; for different soil layers, the mud weight may be selected according to the following data:The cohesive soil an
11、d loam may be used for mud forming on site, and the mud weight is 1.1-1.2;The silty soil and sandy soil shall be used for mud preparation, and the mud weight is 1.5-1.25;The sandy gravel and quicksand layer shall be used for mud preparation, and the mud weight is 1.3-1.5.5. 钻孔灌注桩施工5. Construction of
12、 bored grouting pile（1） 将钻机调平对准钻孔，把钻头吊起徐徐放入护筒内，对正桩位，启动泥浆泵和转盘，等泥浆输到孔内一定数量后，方可开始钻孔。具有导向装置的钻机开钻时，应慢速推进，待导向部位全部钻进土层后，方可全速钻进。正循环钻机开孔时，应先启动泥浆泵和转盘，待泥浆进入孔内一定数量后，方可开始钻进。用泵吸式反循环钻进时，钻头应距孔底 20-30cm，防止堵塞吸渣口，在接长钻杆时，应注意接头紧密，防止漏气、漏水和钻杆松脱。用气举式反循环钻开孔时，钻杆必须在钻孔内埋入水中约 6m，才能扬水排渣。反循环钻进时，必须注意连续补充泥浆，维持护筒内应有的水头，避免坍塌。(1) Firs
13、t level the drill machine aiming at the bored hole, slowly hoist the drill bit and put it into the casting tube, align the pile position; then start up the mud pump and rotary disk; after a certain amount of mud is delivered into the hole, the hole boring may be started.When the drill machine with g
14、ate apparatus starts to bore, it shall be carried forward slowly; after the guiding part entirely drilling into the soil layer, it may be drilled at full speed.When starting holes with the circulation drill, the mud pump and rotary disk shall be started up firstly; after the delivery of a certain qu
15、antity of mud into the hole, drilling may be started.When adopting the suction-pump-type reverse circulation drilling, the drill bit shall be 20-30cm away from the down-hole to avoid the blockage of slag-suction notch; when joining long drill stems, attention shall be paid to guaranteeing the tight
16、joint and avoiding air leakage, water leakage and drill stem getloose.When boring with air-lift-type reverse circulation drill, the drill stem must be embedded into the water for about 6m in the bored hole to pump up water and discharge slag.When adopting reverse circulation drilling, it must be not
17、ed that mud should be supplemented continuously, the due water head in the casting tube should be maintained, and collapse shall be avoided.（2）钻孔应连续进行，不得间断，视土质及钻进部位调整钻进速度。开始钻进及护筒刃脚部位或砂层、卵砾石层中时，应低档慢速钻进。钻进过程中，要确保泥浆水头高度高出孔外水位 0.5m 以上，泥浆如有损失、漏失，应及时补充，并采取堵漏措施。钻进过程中，每进 2-3m 应检查孔径、竖直度，在泥浆池捞取钻渣，以便和设计地质资料核对。
18、(2) Boring hole shall be carried out continuously without interruption, and the drilling speed shall be adjusted based on the soil behavior and drilling position. When starting drilling to the edge foot part or into the sand layer, cobble and gravel layer, the low-grade low drilling speed shall be a
19、dopted. During the drilling process, it should be guaranteed that the height of mud water head is over 0.5m above the water level of hole outside; if having mud loss or leakage, the mud shall be supplemented timely and the leaking stoppage measures shall be taken. During the drilling process, the ho
20、le diameter and verticality shall be inspected by drilling every 2-3m; the boring mud shall be taken from mud sump in order to check with the design and geological data.（3）钻进时，为减少扩孔、弯孔和斜孔，应采用减压法钻进，使钻杆维持垂直状态，使钻头平稳回转。(3) In drilling, the reduced pressure method shall be adopted to make the drill stem
21、maintain vertical and the drill bit stably rotate, in order to reduce reaming, curved hole and inclined hole.（4） 终孔检查合格后，应迅速清孔，清孔方法有抽浆法（适用于孔壁不易坍塌的柱桩和磨擦桩、换浆法（用于正循环钻机） 、淘渣法（适用于冲抓、冲击、成孔，掏渣后的泥浆比重应小于 1.3） 。清孔时必须保证孔内水头、提管时避免碰孔壁。清孔后的泥浆性能指标，沉渣厚度应符合规范要求。不论采用何种方法清孔排渣，都必须注意保持孔内水头，防止坍孔。(4) After the hole is com
22、pleted and is qualified through examination, the hole shall be rapidly cleaned; the hole-cleaning methods include slurry-pumping method (applicable to the column pile and friction pile with the hole wall difficult to collapse), slurry replacement method (for circulation drill), and slag scooping met
23、hod (is applicable to the mud after percussion and grabbing, percussion, hole forming and slag scooping, with a mud weight 1.3). When cleaning the hole, it must keep water head in the hole not touching the hole wall when lifting the tube. The mud property index and dreg thickness after hole cleaning
24、 shall meet the requirements specified in the code. No matter what method is adopted for the hole cleaning and slag discharging, the water head in the hole must be maintained to avoid slumping.（5）清孔后用检孔器测量孔径，检孔器的焊接可在工地进行，监理工程师检验合格后，即可进行钢筋笼的吊装工作。(5) After hole cleaning, the hole inspection instrument
25、 will be used to measure the hole diameter; the welding of hole inspection instrument may be carried out at construction site; after its is inspected to be qualified by the supervision engineer, the hoisting work of reinforcement cage may be carried out.（6）钢筋笼骨架，焊接时注意焊条的使用一定要符合规范要求，骨架一般分段焊接，长度由起吊设备的
26、高度控制，钢筋笼的接长，可采用搭接焊或套管冷挤压连接等方法，钢筋笼安放要牢固，以防在砼浇筑过程中钢筋笼浮起，钢筋笼周边要安放圆的砼保护层垫块。(6) For the reinforcement cage framework, when welding, the usage of welding rod must meet the requirements specified in the code; generally, the framework is welded by section, and its length is controlled by the height of lifti
27、ng rig; for the spreading of reinforcement cage, the overlap welding or casing cold extrusion connection and any other method may be adopted; the placement of reinforcement cage should be firm in case of the floating of reinforcement cage during the concrete pouring process; the filling block of rou
28、nd concrete protective covering shall be placed at periphery of reinforcement cage.（7）水下砼采用导管法进行灌注，导管内径一般为 25-35cm，导管使用前要进行闭水试验（水密、承压、接头抗拉） ，合格的导管才能使用，导管应居中稳步沉放，不能接触到钢筋笼，以免导管在提升中将钢筋笼提起，导管可吊挂在钻机顶部滑轮上或用卡具吊在孔口上，导管底部距桩底的距离应符合规范要求，一般 0.25-0.4m，导管顶部的贮料斗内砼量，必须满足首次灌注剪球后导管端能埋入砼中 0.8-1.2m，施工前要仔细计算贮料斗容积，剪球后向导管
29、内倾倒砼宜徐徐进行防止产生高压气囊。施工中导管内应始终充满砼。随着砼的不断浇入，及时测量砼顶面高度和埋管深度，及时提拔拆除导管，使导管埋入砼中的深度保持 2-6m 间。砼面检测锤随孔深而定，一般不小于 4Kg。(7) The tremie method will be adopted for the grouting of underwater concrete; generally the internal diameter of duct is 25-35cm; the closed water test (watertight, pressure-bearing, tensile joi
30、nt) shall be carried out before the usage of duct, and only the qualified duct can be used; the duct shall be placed steadily and deep in the center and free from touching the reinforcement cage, in case that the duct will lift the reinforcement cage in hoisting; the duct may be suspended at the pul
31、ley of drill top or at the orifice with clamping apparatus; the distance from the duct bottom to the pile bottom shall meet the requirements specified in the code, and generally be 0.25-0.4m; the concrete quantity in the concrete bin at the duct top must meet the condition that the duct end can be e
32、mbedded into the concrete for 0.8-1.2m after the first cut-ball grouting; the volume of concrete bin shall be calculated carefully before construction, and the dumping of concrete into the duct after the ball cutting should be carried out gradually, avoiding the generation of high pressure airpocket
33、. The duct shall be always filled up with concrete during construction. With the continuous pouring in of concrete, the measurement of concrete top surface depth and pipe laying depth, elevating and removing duct shall be carried out timely, to make the depth of duct embedded into concrete maintain
34、2-6m.The inspection hammer of concrete surface is determined by the hole depth and generally not less than 4kg.（8）每根导管的水下砼浇筑工作，应在该导管首批砼初凝前完成，否则应掺入缓凝剂，推迟初凝时间。(8) The underwater concrete pouring work of each duct shall be completed before the first batch concrete initial set of this duct, otherwise re
35、tarder shall be blended in to put off the time of initial set.（9）砼的坍落度应满足设计要求，砼浇筑应连续进行，为保证桩的质量，应留比桩顶标高高出 0.5-1.0m 左右的桩头，处于干处的桩头，可在砼初凝后，终凝前清除。(9) The slump of concrete shall meet the design requirements and the pouring of concrete shall be carried out continuously; the pile head which is about 0.5-1.
36、0m higher than the elevation of pile top shall be remained, to guarantee the pile quality; the pile head in dry condition may be cleaned up after the initial set and before the final set.（10） 技术人员应对钻孔灌注桩各项原始记录及时进行整理签认。(10) Technical personnel shall timely arrange and endorse the original records of
37、bored grouting pile.6. 环保措施为保护施工范围内的环境卫生、农田，钻孔桩废弃的泥浆应在施工完成后，用汽车或罐车将泥浆池（槽）中的泥浆清运到指定的排放地点。6. Environmental protection measures In order to protect the environmental sanitation and farmland within the scope of construction, the waste mud in the mud sump (tank) of drill pile shall be removed and deliver
38、ed to designated discharging place with automobile or tank car after the completion of construction.7. 工艺流程7. Technological process（做好记录和签认手续） (Complete recording and endorsing procedures) （ (做好各项记录，监理工程师批准）(Complete each record, approvedby the supervision engineer)8. 主要机械设备钻机、砼搅拌机、砼运输车、吊车、空压机、水泵、导管
39、、泵车、装载机、电焊机、发电机、水车等。测量定位Measurement and Location填筑工作平台Filling working platform场地平整Ground leveling埋设护筒Burying casting tube 制做护筒Making casting tube复核放样 Double-checking and setting-out钻机就位Drill machine in position 钻孔Boring hole合格泥浆Qualified mud泥浆池Mud sump清孔Hole cleaning终孔 Final hole终孔检查Inspection of fi
40、nal hole钢筋笼就位Reinforcement cage in position下导管Down-duct检查 Inspection钢筋笼制作Reinforcement cage making导管拼接检查Inspection of duct jointing测量复核定位Measuring the double-checked position检查隔水设施Checking water-proof facilities水下灌注砼Underwater grouting concrete砼运输Concrete transportation砼试验Concrete test拔出护筒Pulling ou
41、t the casting tube成桩检测Inspection of formed pile砼的拌合Concrete mixing8. Major mechanical equipments Drill machine, concrete blender, concrete carrier vehicle, crane, air compressor, water pump, duct, pump truck, loading machine, electric welding machine, generator and waterwheel, etc.附：钻机性能比较表如下：Annex:
42、 The performance comparison table of drill machine is as follows:钻机型号Drill machine model成孔直径Diameter of pore formedm钻深Drill depthm转盘转速Rotation speed of rotary diskr/min最大钻矩Maximum drill torqueKNM主机功率Mainframe powerKW钻机重weight of drill machinetKR2500A（河北星河厂）(Hebei Xinghe Factory)1.8-2.5 80 20 50 222=44 32KP2000（郑州勘探厂）(Zhengzhou Exploration Factory)1.5-2.0 100 63 39 45 20S-500（台湾）(Taiwan)1.5-2.5 90 42 150 320 28GPS-25（上海探矿厂）(Shanghai Prospection Factory)1.5-2.5 100 20 30 37 28GPS-20（上海探矿厂）(Shanghai Prospection Factory)1.5-2.5 80 20 30 30 22
