后压浆施工+技术规范

后压浆施工技术规范

Technical Specification of Post Pressure Grouting

一、设计design

1、对桩径800mm桩长40m采用复式注浆法即桩端与桩侧注浆法。桩端与桩侧各对称安装二根注浆管。

Double pressure grouting to be adopted for 800mm dia./40m long pile, i.e. side and bottom grouting. Two grouting pipes shall be arranged for bottom and side respectively.

2、注浆位臵grouting position：

1）桩端注浆：注浆花管应埋入终孔孔底下100-300mm，

Bottom grouting: grouting pipe should penetrate 100-300mm below the bottom of borehole.

2）桩侧注浆：桩长30m/40m的桩注浆花管应设臵在地面下20m/25m处的砂层中，或者15-20m/20-25m处的砂层与粘性土层界面上500mm处，具体位臵由各区段工勘探孔及桩钻进时的反渣情况综合判断确定，同一建（构）筑物注浆位臵宜相同（详见附图二）。

Side grouting: grouting pipes for 30m/40m piles should be embedded in sand strata 20m/25m underground, or 500mm above the intersection of

15-20m/20-25m silty sand and clay sand. Exact positions shall be reasonably decided as per out-coming soil condition in test boring and actual piling. Grouting position for the same structure (building) is preferably identical. (see diagram 2)

3、注浆管的长度：由实际施工的孔深确定，其长度为实际孔深+0.6m。

Length of grouting pipe: shall be as per actual borehole depth and should be 0.6m longer than borehole depth.

4、注浆管采用DN20、δ=2.75的焊管，相邻注浆管采用丝扣连接，并用14#

铁丝绑扎固定在钢筋笼的外侧。注浆管底端用丝堵封闭，距底端400mm长度范围内对称均匀钻12个φ6的注浆孔，用胶带及图钉封孔。注浆管顶部应高出砼面0.5以上，且高出地面0.2-0.3m。管顶要用丝堵封闭且用不同颜色的胶带缠绕，将桩底注浆管与桩侧注浆管区分开来。

Grouting pipe type: DN20、δ=2.75 welded pipe to be adopted, and adjacent

pipes to be connected with threads and tightly fixed to the outer side of rebar cage with 14# galvanized wire. Bottom end of grouting pipe to be sealed with plug and 12 nos ofφ6 grouting holes to be evenly drilled within the bottom 400mm of grouting pipe, and the same should be sealed with tapes and thumbnails. Top of grouting pipe should be 0.5m above concrete level and 0.2-0.5m above ground level. Pipe tops to be sealed with plugs and wrapped with tapes of different colors to differentiate bottom and side grouting pipes.

5、注浆压力：桩侧：桩长30m为1.5 MPa，桩长40m为2.0 MPa ；桩端：桩长30m为2.0 MPa，桩长40m为2.5MPa。

Grouting pressure：pile side: 1.5MPa for 30m piles and 2.0Mpa for 40m piles; pile bottom: 2.0MPa for 30m piles and 2.5 for 40m piles.

6、注浆材料及注浆量：采用普通42.5级水泥，每根桩水泥用量暂定为3.0t。初始压浆时水灰比为1：1，体积为200L，余下水灰比为08:1。

Grouting material and quantity: normal OPC 42.5 grade cement to be adopted and 30t of cement for each pile. Initial grouting water-cement ratio should be 1:1, volume should be 200L and trailing water-cement ratio should be 8:1.

7、成桩2天后开始注水打开通道。28天内进行注浆。

Water to be injected into grouting pipes after 2 days of pile concreting completion so as to clean grouting pipes and pressure grouting to be carried out within 28 days of pile completion

8、注浆顺序：先桩侧后桩底，二者时间间隔不小于2小时。先外围后中间。注浆点距未施工或者正在施工的桩的最小距离为15m。

Grouting sequence: first pile sides and then pile bottom and minimum 2 hours interval to be maintained between the two; first outer and then inner and minimum clearance between pressure grouting pile and installation on-going piles should be at least 15m.

9、终止注浆条件：采用注浆压力与注浆量双控，以注浆量控制为主，注浆压力控制为辅。

Condition for pressure grouting suspension: two references to be considered, i.e. grouting pressure and grouting quantity whereas the latter should be taken as

primary and the former secondary.

二、范围scope：

1、烟囱基础（内4圈除外）；446根

Chimney foundation (excluding inner 4 circles)，total 446nos

2、全部三个水塔的环基基础；每个水塔约552根，共1656根

Ring beam foundation of three NDCT.Each CT 552nos，total 1656nos

3、其他需要后压浆的基础，现场与业主协商确定。

Other foundations that requires pressure grouting—to be discussed with the Owner at site.

三、施工方案methodology

1、工艺流程technique steps：

后压浆工艺流程为：制作压浆管→安装压浆管→检查压浆管质量→灌注混凝土→打开压浆管，并做注水试验→配制水泥浆，桩侧压浆→配制水泥浆，桩底压浆→养护。

Steps of post pressure grouting: grouting pile fabrication---grouting pipe installation---grouting pipe quality inspection-concreting---open pressure grouting pipe and water injection test---cement slurry mixing and side grouting---cement slurry mixing and bottom grouting---curing

2、注浆管制作grouting pipe fabrication：

1）注浆管材料grouting pipe material：

采用DN20壁厚2.75mm的焊管。

Welded pipe of DN20 and 2.75mm thick

2）注浆管的制作fabriaction：

采用车丝机在焊管的二端车丝，每个车丝段的长度为50mm，车出来的丝应平正圆滑，不得出现偏丝滑丝，若出现应用切割机将该段切除后重新车丝。车丝后应用生胶带缠绕3-5圈，然后在下节管的上端安装直通并拧紧。安装时应用管钳拧紧，防止在整个注浆管管道安装过程中出现脱离或者是不封闭，导致漏浆现象的发生。同时根据实际孔深制作相应的短节，短节的二端按上述要求车丝。

Thread to be made at two ends of grouting pipe with threading machines and length of each thread should be 50mm. Threads made should be smooth and even, and distorting or sliding threads are not allowed. In case distorted or slide threads are made, the same should be chopped and remade. Finished threads should be wrapped with 3-5 rounds of thread tape, and then straight coupling shall be tightly fixed to one end of the pile with pipe wrench so as to avoid leakage or disconnection during pressure grouting. Grouting pipes shall be prepared in view of pile depth and threads of connections shall be made as required.

3）注浆花制作perforated grouting pipe

距底端400mm内对称均布钻12个φ6的孔，在每对孔的断面用胶带缠绕3圈，然后将图钉安放在孔的位臵，再在图钉的外侧用高压绝缘胶带缭绕3-5圈（详见附图3）。桩底注浆花管底口采用焊接方式将圆钢车成的圆锥状丝堵焊牢密封（详见附图3）。桩侧注浆花管的底口采用相配套的外丝堵密封。

12 nos of holes to be symmetrically and evenly drilled within bottom 400mm of grouting pipe and wrap 3-5 rounds of tapes around each pair of holes and then pin thumbnails at the holes, then again wrap 3-5 round of high-voltage insulation tape outside the nails (see diagram 3). The bottom of the grouting pipe shall be sealed with suitable external plug.

3、注浆管的安装installation of grouting pipe：

1）注浆管位臵及长度的确定grouting position and pipe length：

（1）桩底注浆管的底端应设臵在实际孔深以下100mm处，注浆花管应埋设在沉渣及孔底原状土中。长度为实际孔深+0.1m。烟囱为41m（-5～-46 m），水塔为43.8m（-1～-44.8 m）。

Bottom grouting pipe should penetrate 100mm under the bottom of borehole and perforated section should be embedded in bottom sediment. Pipe should be 0.1m longer than actual borehole depth.

（2）桩侧注浆管应设臵在距设计桩底标高约15m处的粉砂层中。长度为25m+桩位处自然地面至设计桩顶的距离。烟囱（-5～-29 m）与水塔（-1～-25m）均为24m。

Side grouting pipe should be embedded in silty sand 15m above design pile bottom. The length of grouting pipe should be 25m plus the distance between ground elevation and design pipe top elevation.

（3）同一断面上桩底注浆管与桩侧注浆管应对称均布。

Bottom grouting pipe and sides grouting pipe on the same section should be arranged symmetrically.

2）注浆管安装grouting pipe installation：

（1）二次清孔期间，应将注浆管运到桩孔附近，并根据实际孔深按上述要求核算注浆管的长度，无误后方可安装。

During second time flushing, grouting pipes should be gathered around borehole. Grouting pipe length should be calculated exactly according to actual borehole depth and be lowered after sound confirmation.

（2）注浆的安装与钢筋笼的安放同时进行。桩底注浆管底部500mm处应内折15°防止在注浆管下放过程中挂碰孔壁。

Grouting pipe should be lowered together with rebar cage. Grouting pipe should be bended inward with 15-25°angle at 500mm above pipe end to avoid clashing with borehole sides while lowering.

（3）注浆管与钢筋笼的主筋采用14#铁丝绑扎固定。注浆管绑扎在钢筋笼的外侧。桩底注浆管的底部15m范围内每2m设一绑扎点，其余部位及桩侧注浆管每4m 设一绑扎点。

Grouting pipe should be fixed with main reinforcement bar using 14# galvanized wire. Grouting pipe should be fixed outside of cage. Bottom grouting pipe should be fixed every two meters with cage within the bottom 15m, and remaining part and side grouting pipes to be fixed with cage every 4 meters.

（4）相邻上下节注浆管采用带丝扣的直通连接，安装时应用管钳拧紧，防止在整个注浆管管道安装过程中出现脱离或者是不密实导致漏浆现象的发生。Adjacent two grouting pipes shall be tightly connected with straight coupling using pipe wrench so as to avoid disconnection or leakage during grouting.

（5）在钢筋笼孔口搭接前，应对压浆管进行注水，检查其密封性，当压浆导

管内注满清水后，水面能够保持稳定且不升降，证明密封完好。否则，提起钢筋笼检查漏水原因，满足要求后方可下另一节笼，下笼时要徐徐放入，严禁用力墩下或者扭动。

When lapping rebar cages at borehole, water should be injected to grouting pipe to check its imperviousness. The same can be confirmed if level of clean water in grouting pipe remains steady. Otherwise, cage should be lifted to find out leaking points, after which the next section of cage can be lowered. Cage should be lowered with care and jerking or sudden free fall is not allowed.

（6）下笼结束后，在压浆管上口拧上堵头，以免杂物掉入压浆导管内而使管路不畅。并用不同颜色的油漆将桩底注浆管与桩侧注浆管区分开来，以免混淆。

After full cage is lowered, grouting pipe top opening should be sealed to avoid foreign stuff from falling in and blockage. Exposed grouting pipes should be painted with different colors to differentiate bottom and side grouting pipes.

4、注浆pressure -grouting

1）注浆设备：Grouting equipments

（1）采用SNS-6/10注浆泵，注浆额定压力为10MPa，额定流量为100L/min。

（2）压浆泵控监测压力表为2.5级16MPa抗震压力表。

(3) 浆液搅拌机为与注浆泵相匹配的YJ-340型液浆搅拌机，容积为0.34m3，功率4kW。

(4) 水泥浆液的输浆管应采用高压流体泵送软管，额定压力不小于20MPa。

1) Use SNS-6/10 grouting pump, grouting rated pressure 10MPa, rated flow 100L/min.

2) Pressure gauge for grouting pump shall be Grade 2.5 16MPa seismic pressure gauge.

3) Grouting batching machine is YJ-340 batching machine which matches

with grouting pump, Volume of 0.34m3, power 4kW.

4) Grout transmission pipe shall be high pressure flow-pumped soft pipe,

rated pressure shall be minimum 20MPa.

2）注浆材料及注浆量：grouting material and volume

（1）采用PPC 或OPC42.5水泥，每根桩水泥用量暂定为2-3.0t，其中桩端水泥用量约为2.0t，桩侧水泥用量约为1.0t。合理的压浆量应由桩端、端侧土层类别、渗透性能、桩径、桩长、承载力增幅要求、沉渣量有泥皮厚度等诸因素确定。在实际施工过程中,需要根据压水试验情况及压浆过程中的反应适当高速注入量,并通过对压浆压力、浆液浓度、压浆方法诸因素的调控,将所需压浆量控制在设计要求的范围内。一般浆液浓度和灌浆量大,灌浆压力高,加固效果更好。

Use PPC or OPC42.5 cement. Volume for each pile temporarily shall be

2-3.0t, among which about 2.0t to be applied at pile bottom and about 1.0t to be applied at pile side. Right grouting volume shall be fixed according to pile bottom& side earth catalogue, permeability, pile dia, pile depth, increasing capacity requirement, sediment thickness etc other factors. During actual construction, proper amount of grout shall be poured at high speed based on pressure-watering test condition and pressure-grouting process reaction. Also, required grouting volume shall be kept as per design requirement through adjustment of grouting pressure, grout density and grouting methodology etc. Usually, reinforcing effect will be better under high density, large volume and high grouting pressure.

（2）初始压浆时水灰比为1：1，体积为200L，余下水灰比为0.6:1。泵送流量控制在2.0m3/h 左右。不同浓度的泥浆体其特性有所不同：稀泥浆(水灰比约为

1-0.8：1)便于输送,渗透能力强,用于加固预定范围的周边地带；中等浓度泥浆体(水灰比约为0.6：1)主要加固预定范围内的核心部分,在这里中等浓度泥浆体起填充、压实、挤密作用；而浓泥浆(水灰比为0.4：1)的灌注则对已注入的泥浆体起脱水作用。不同阶段,调配不同浓度的压浆浆液,并采用相应的压浆压力,浆液浓度控制原则为：依据压水试验情况选择初注浓度,通常先用稀泥浆、随后渐浓,最后压浓浆。在可灌的条件下,尽量多用中等浓度以上的浆液,以防浆液作无效扩散。

At initial stage, water cement ratio shall be 1：1, volume 200L; following water cement ratio shall be 0.6:1. Pumped flow shall be controlled around 2.0m3/h. Characteristics of different density grout differs: thin grout (water cement ratio about 1-0.8:1) is easy for transmission with high permeability and is applied for solidify edge part of intended area; medium density grout (water cement ratio 0.6：

1) is mainly applied for solidifying core part of intended area, here medium density grout is mainly for fulfilling, compacting and squeezing function. For thick density grout (water cement ratio about 0.4:1), it is mainly for dehydration of poured grout. At each stage different density grout shall be mixed and applied with corresponding grouting pressure. Principle for grout density control is: based on pressure-watering condition to fix initial grouting density, usually process is to start from thin grout and gradually increase density until finally apply thick density grout. Under pourable condition, density of medium or above shall be applied as much as possible to avoid grout spreading in vain.

(3)注浆应对同一根桩的各注浆管依次实施等量注浆。

Grouting for each grouting pipe of one pile shall be done one by one with equivalent volume.

3）注浆压力：grouting pressure

桩侧：桩长30m为1.5 MPa，桩长40m为2.0 MPa ；桩端：桩长30m为2.0 MPa，桩长40m为2.5MPa。

Pile side: 30m pile: 1.5 MPa, 40m pile: 2.0 MPa;

Pile bottom: 30m pile: 2.0 MPa, 40m pile: 2.5MPa.

4）注浆时间：Grouting time

成桩2天后开始注水打开通道并进行压水试验。压水试验是压浆施工前必不可少的重要工序。成桩后至实施桩侧、桩底压浆前,通过压水试验来确认桩底的可灌性。压水试验是选择压浆工艺参数的依据之一。此外,压水试验还能探明并疏通压浆通道,提高桩底可灌性。

Water shall be injected in after 2 days from pile casted for opening pipe for water pressure test. Water pressure test is one integral and important part prior to pressure grouting. After pile casted and till pile side and bottom grouting, it is applied to check whether pile bottom can be poured or not. Water pressure test is one parameter data for selecting grouting workmanship. Besides, it can also check and dredge grouting pipe to enhance pouring smoothness of pile bottom.

28天内进行注浆。初注时一般压力较小,浆液亦由稀到稠。初注时要密切注意压浆压力、压浆量和压浆皮管的变化,并注意压浆节奏。压浆过早,将会因为桩体强度、

桩侧阻力过低面导致浆液溢出地面造成压浆失败；压浆太晚,会因桩身泥皮硬化而影响向上泛浆挤入桩周体而导致浆液向远处流失达不到最佳压浆效果。

Grouting shall be conducted within 28 days. Initial grouting is usually done with low pressure; also grout shall be gradually thickened. Grouting pressure, volume and grouting pipe change shall be paid proper attention to, so is grouting rhyme. If pressure grouting is done earlier, it might fail due to low pile strength and pile frictional resistance leading to grout overflowing above earth. If later, it can’t achieve optimal performance due to pile surface slurry solidification which affects grout upward spreading to fulfill surroundings of pile while causing grout to spread towards remote.

桩侧注浆完成时间约40min，桩端注浆时间约70min。桩侧注浆完成后120min 后方可进行桩端注浆。

Pile side grouting takes about 40min, pile bottom grouting takes 70min. Pile bottom grouting can be started 120min after completion of pile side grouting.

5）注浆节奏Grouting rhyme

为了使用有限浆液尽可能充填并滞留在桩底有效空间范围内,在压浆过程中还需掌握压浆节奏,实行间歇压浆。间歇时间的长短需依据压水试验的结果而定,并在施注过程中依据压浆压力变化,判断桩底可灌性现状加以调节。间歇压浆的节奏需掌握得恰到好处,既要使压浆效果明显,又要防止因间歇停注时间过长堵塞通道而使浆液沿桩周上冒现象,此时应在注入一定浆液后暂停1～2 天,待桩周浆液凝固后,再施行压浆,可达到设计要求的压浆量。

In order to fully utilize certain grout to fulfill and remain at effective space to the possible efficiency and extent, during pressure-grouting, grouting rhyme shall be maintained and interval grouting methodology shall be adopted. Interval time shall be fixed according to pressure-watering test result; at the same time, during grouting, pile bottom pourable shall be concluded and adjusted accordingly in accordance with change of grouting pressure. Rhyme of interval grouting shall be maintained to the possible extent to ensure obvious grouting effectiveness and at the same time, avoid grout spreading upwards due to block of pipe lead to by over stoppage of interval grouting in which case 1-2 days shall be paused after pouring

of certain grout and till pile side grout solidified can pressure-grouting be proceeded thus to meet design grouting quantity.

6）注浆顺序：Grouting sequence

（1）同一根桩先桩侧后桩底，二者时间间隔不小于2小时。

For one pile, first pile side grouting, then pile bottom. Gap between these two steps shall be minimum 2 hours.

（2）群桩先外围后中间。

For group piles, grouting shall be executed from outside towards inner center.

（3）注浆点距未施工或者正在施工的桩的最小距离为10m。

Grouting pump location shall be over 10m from nearest non-started pile or ongoing pile.

7）压浆时应注意观察是否有浆液上溢，一旦发现上溢反浆，即时停止。

Attention shall be paid to whether there is any overflow of grout while pressure-grouting and on observation of which grouting shall be stopped immediately.

8）压浆过程中注意安全，要求无关人员远离压浆接口处，防止压浆管爆裂伤人。拆除压浆管时，要注意高压管中带压力的浆液射出，压浆口不要正对操作人员。

Safety shall be taken care while grouting. Irrelevant personnel shall be away from interface joints of grouting in case getting hurt from busting of grouting pipe. While dismantling grouting pipe, attention shall be paid to injection of pressurized-grout from high-pressure pipeline; grouting open shall not be directly facing operators.

9）注浆控制标准、终止注浆条件：

采用注浆压力与注浆量双控，以注浆量控制为主，注浆压力控制为辅。

当满足下列条件之一时可终止注浆：

注浆总量和注浆压力均达到设计要求；

注浆总量已达到设计值的75%，且注浆压力超过设计值。

当注浆压力长时间低于正常值或地面出现冒浆或周围桩孔串浆，应改为间歇注浆，间歇时间宜为30~60min，或调低浆液水灰比。

后注浆施工过程中，应经常对后注浆的各项工艺参数进行检查，发现异常应采取相应处理措施。当注浆量等主要参数达不到设计值时，应根据工程具体情况采取相应措施。

Grouting control standard; grouting stop conditions:

Double control, that is grouting pressure and volume shall be adopted while taking grouting volume as dominant reference and grouting pressure subsidiary.

Grouting can be stopped once one of following conditions is met:

Grouting total volume and pressure both meet design requirement.

Grouting total volume has met 75% of design volume and grouting pressure exceeds design value.

Interval grouting shall be adopted when grouting pressure has been below normal value for long or grout overflows to surface or spreads to adjacent piles. Interval time shall be maintained at 30-60min or to decrease water cement ratio.

While post pressure-grouting goes on, various parameters of workmanship shall be checked frequently and once abnormity detected, corresponding treatment measures shall be taken immediately. Corresponding measures shall be taken based on actual conditions when grouting volume etc main parameters can’t meet design value.

10）后注浆桩基工程质量检查和验收应符合下列要求：

后注浆施工完成后应提供水泥材质检验报告、压力表检定证书、试注浆记录、设计工艺参数、后注浆作业记录、特殊情况处理记录等资料；

Post pressure-grouting piling work quality check and acceptance shall confirm to following requirements:

Documents such as cement test report, pressure gauge calibration certificate, trial grouting record, design workmanship parameters, post pressure-grouting construction record, special condition treatment record etc shall be submitted after completion of post pressure-grouting.

11）压浆后期的保养龄期

压浆的保养龄期即桩底压浆后多少时间后可以做静载试验或作为工程桩使用的龄期,通常要求压浆后保养15 天左右。

Curing period after pressure-grouting

Curing period, that is, after how long from pile bottom grouted can integrity test be done or can it be deemed as working piles. Usually, 15 days curing from grouting completion is required.