阅读说明：本技术 一种地基处理强夯置换加固方法 (Dynamic compaction replacement reinforcing method for foundation treatment ) 是由 陈贵山 于 2021-11-02 设计创作，主要内容包括：本发明公开了一种地基处理强夯置换加固方法,包括：前期工程准备；根据现场地质及周边环境设计合理的强夯置换法；对地基进行初步平整以及添加多道防护措施；试夯以及试夯效果检测；地面标高测量；夯点测放；再次对场地平整,并进行满夯施工；强夯检测及验收。本发明使用工地常备简单设备,施工工艺简单,适用土质范围广,可取得较高的承载力,一般地基强度可提高3-5倍；变形沉降量小,压缩性可降低5-10倍,工期快,节省原材料和投资,降低费用；与预制桩加固地基相比可节省投资60％-70％；与砂桩相比可节省投资50％-70％,能达到对目标软弱地层的精确置换,使厚软土层地基固结,提高地基强度,且效率更高。(The invention discloses a dynamic compaction replacement reinforcing method for foundation treatment, which comprises the following steps: early-stage engineering preparation; designing a reasonable dynamic compaction replacement method according to the field geology and the surrounding environment; primarily flattening the foundation and adding a plurality of protection measures; testing ramming and testing ramming effect; measuring the ground elevation; measuring and placing rammed points; leveling the site again, and performing full-compaction construction; and (5) detecting and accepting dynamic compaction. The invention uses the construction site conventional simple equipment, has simple construction process and wide applicable soil property range, can obtain higher bearing capacity, and generally can improve the foundation strength by 3-5 times; the deformation settlement amount is small, the compressibility can be reduced by 5-10 times, the construction period is short, raw materials and investment are saved, and the cost is reduced; compared with the precast pile reinforced foundation, the investment can be saved by 60-70%; compared with sand piles, the method can save investment by 50-70%, can achieve accurate replacement of a target soft stratum, enables a thick and soft soil layer foundation to be consolidated, improves the strength of the foundation, and has higher efficiency.)

1. A dynamic compaction replacement reinforcing method for foundation treatment is characterized by comprising the following steps:

s1, preparing an early stage project;

s2, designing a reasonable dynamic compaction replacement method according to the field geology and the surrounding environment;

s3, primarily flattening the foundation and adding a plurality of protective measures;

s4, testing ramming and testing ramming effect;

s5, measuring the ground elevation;

s6, measuring and releasing a tamping point;

s7, leveling the site again, and performing full-compaction construction;

and S8, detecting and accepting dynamic compaction.

2. The dynamic compaction, replacement and reinforcement method for foundation treatment according to claim 1, wherein the method comprises the following steps: the step S1 includes:

s101, surveying a site and a surrounding environment on site, and determining a part needing dynamic compaction replacement by combining a design drawing;

s102, removing surface soil of the field, namely excavating out the floating soil with the depth of 1.0-1.5 m, and backfilling the leveled field with strongly weathered broken stones to a reference elevation;

s103, preparing construction machinery, field personnel and materials, and having start-up conditions;

s104, determining surrounding buildings and underground conditions according to the related data;

the dynamic compaction, replacement and reinforcement method for foundation treatment according to claim 1, wherein the method comprises the following steps: the step S3 includes:

s301, determining the positions and the number of tamping points for dynamic compaction replacement of a site, wherein the tamping points are arranged in a regular triangle, square or quincunx shape, the distance between the tamping points can be 2.0-5.0 m, and all the tamping points of a foundation are numbered;

s302, hole leading is carried out at the determined part to be dynamically compacted and replaced, then layered filling is carried out on the hole leading, then repeated tamping is carried out on the layered filling in the hole leading, a method of flushing and slurry extracting is adopted to carry out hole expanding on an interlayer of the soft foundation along the radial direction, the layered filling is continued after the hole expanding is finished, then repeated tamping is carried out on the filling in the interlayer of the soft foundation again, wherein the maximum diameter of the hole expanding is twice of the diameter of the hole leading;

and S303, calculating specific parameters of dynamic compaction replacement, including the number of times of compaction, the interval time of compaction and the fall distance of compaction.

3. The dynamic compaction, replacement and reinforcement method for foundation treatment according to claim 1, wherein the method comprises the following steps: the step S4 includes:

s401, estimating an average ground elevation value possibly generated after dynamic compaction replacement construction in advance, determining the height of the ground before compaction according to the average ground elevation value, and leveling by using a bulldozer;

s402, when the surface soil of the field is soft or the underground water level is high, reducing the underground water level or paving a layer of loose material with a certain thickness on the surface layer, and adopting waterproof measures such as digging a drainage ditch and the like;

s403, when vibration generated by dynamic compaction replacement construction has harmful influence on adjacent buildings or equipment, setting monitoring points, and taking shockproof measures such as digging shock insulation ditches and the like;

s404, setting a working area and a safety range, pulling a warning line to assign a special person to watch, and strictly forbidding the entry of irrelevant persons.

4. The dynamic compaction, replacement and reinforcement method for foundation treatment according to claim 1, wherein the method comprises the following steps: the step S6 includes:

s601, according to a construction drawing and a coordinate control network laid on site, measuring and placing the position of a tamping point by using a theodolite or a total station, and marking out a tamping point central point by using an obvious mark or marking out a tamping point central point by using a lime point;

s602, rechecking the tamping point pay-off before each tamping;

s603, when the rammer is in place, overlapping the center of the rammer and a measured ramming point, and drawing a lime ring by taking the ramming point as the center;

s604, before and during tamping, a sliding staff is used for standing on the hammer top, a special measurer is used for measuring the elevation of the hammer top by using a leveling instrument, each time of tamping is carried out once, the difference value of the two times before and after tamping is the tamping settlement of the tamping, and the final two-stroke tamping settlement meets the design requirement and serves as the tamping stopping standard.

5. The dynamic compaction, replacement and reinforcement method for foundation treatment according to claim 1, wherein the method comprises the following steps: the step S7 includes:

s701, cleaning and leveling the construction site again;

s702, marking tamping points, measuring the elevation of a field, guiding holes at the determined tamping points, filling the guiding holes in a layered mode, repeatedly tamping the layered filling in the guiding holes, reaming the interlayer of the soft foundation in the radial direction by adopting a method of flushing and slurry extracting, continuing to fill the filling in the layered mode after reaming, and repeatedly tamping the filling in the interlayer of the soft foundation again;

s703, positioning the crane, arranging the rammer above a ramming point position, aligning the rammer to the ramming point position by adopting the point rammer with the diameter of 1.5-2.0 m, and measuring the height of the top of the hammer before ramming;

s704, hoisting the rammer to a preset height, starting a unhooking device, putting down a lifting hook after the rammer freely falls down, and measuring the height of the top of the hammer; if the rammer is inclined due to the inclination of the pit bottom, filling the pit bottom in time;

s705, repeatedly tamping, repeatedly backfilling, tamping again after filling, tamping again after tamping, and continuously circulating for 10-30 times;

s706, intermediate checking;

and S707, hammer withdrawing.

6. The dynamic compaction replacement reinforcing method for foundation treatment according to claim 6, wherein: the step S706 includes:

s7061, in the construction process, measuring the tamping settlement of each strike by adopting a level gauge every time of tamping, recording the times of filling and the filling amount of each strike, and recording data;

s7062, when the deflection hammer phenomenon is detected, the bottom of the ramming pit is leveled except for adjusting the suspension arm;

s7063, when the rammed pit discharges water, timely backfilling stone, and keeping the distance between the bottom of the hammer and the water level to be not less than 1.0 m; s7064, when the periphery of the tamping pit is excessively raised, timely digging out the raised part;

s7065, checking the backfill stone to meet the design requirement.

7. The dynamic compaction replacement reinforcing method for foundation treatment according to claim 3, wherein the method comprises the following steps: the filling material adopts gravel sand in the field, and graded gravel is mixed according to the gravel-sand ratio of 7:3, so that the gravel is embedded into the soil layer to be reinforced under the action of high energy of dynamic compaction replacement and is tightly combined with surrounding sand, and the compactness of the foundation soil layer is improved.

Technical Field

The invention relates to the technical field of foundation reinforcement methods, in particular to a foundation treatment dynamic compaction replacement reinforcement method.

Background

The foundation refers to the soil or rock mass of the supporting foundation under the building, and the foundation is equivalent to the 'life' of a building. The foundation is not well beaten, no matter how delicate the building cover is, but the foundation is askew, and the foundation is also a defective product or even a dangerous house. Therefore, when the foundation is dug, the foundation needs to be reinforced, and a common reinforcing method is a dynamic compaction method, wherein a heavy hammer with the weight of 8-40 tons freely falls from the height of 6-40 meters to perform the treatment of dynamic compaction on the foundation. The bearing capacity of the foundation subjected to dynamic compaction can be improved by 3-4 times to 6 times, the compressibility can be reduced by 200-1000%, and the influence depth is more than 10 meters.

The dynamic compaction method is widely applied to reinforcement of foundation soil with poor soil quality, and has the characteristics of convenient construction, obvious cost advantage and the like. At present, the dynamic compaction design still estimates construction parameters mainly according to the experience of engineers or empirical formulas and is determined by field trial compaction. The empirical formula is generally a quantitative relation between the size of a dynamic compaction reinforcement range (generally consisting of a ramming pit depth, an effective reinforcement depth and a lateral reinforcement range) and different construction parameters (ramming energy or ramming impulse per hammer, ramming hammer size and ramming times) under the condition of a single ramming point established according to engineering examples, model tests or numerical calculation results, and can provide convenience for selection of the construction parameters in the dynamic compaction design, but the dynamic compaction construction has requirements on the size of the reinforcement range and the soil body encryption degree in the reinforcement range, so that the estimated construction parameters have larger errors only through the empirical formula related to the size of the reinforcement range without considering the soil body encryption degree in the reinforcement range, thereby reducing the trial compaction efficiency and causing the waste of construction cost. In addition, because the actual dynamic compaction construction site is composed of a series of tamping points, related parameters of multiple tamping points such as the distance between the tamping points and the like are required to be determined before the dynamic compaction construction, and simultaneously, because an overlapping area exists between adjacent tamping points and is influenced by peripheral tamping points, the interaction between the adjacent tamping points is required to be considered.

The soft soil layer of some foundations is thicker, the foundation treated by a general dynamic compaction method has soil layer consolidation on the upper surface, while deep loose filling soil is still in a loose state and cannot be consolidated and compacted to meet the design requirements, and particularly, when mucky soil, silty clay and cohesive soil with large water content are constructed in the field, the strengthening effect is difficult to show.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a foundation treatment dynamic compaction replacement reinforcing method, and can effectively solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a dynamic compaction replacement reinforcing method for foundation treatment comprises the following steps:

s1, preparing an early stage project;

s2, designing a reasonable dynamic compaction replacement method according to the field geology and the surrounding environment;

s3, primarily flattening the foundation and adding a plurality of protective measures;

s4, testing ramming and testing ramming effect;

s5, measuring the ground elevation;

s6, measuring and releasing a tamping point;

s7, leveling the site again, and performing full-compaction construction;

and S8, detecting and accepting dynamic compaction.

As a preferred embodiment of the present invention, the step S1 includes:

s101, surveying a site and a surrounding environment on site, and determining a part needing dynamic compaction replacement by combining a design drawing;

s102, removing surface soil of the field, namely excavating out the floating soil with the depth of 1.0-1.5 m, and backfilling the leveled field with strongly weathered broken stones to a reference elevation;

s103, preparing construction machinery, field personnel and materials, and having start-up conditions;

s104, determining surrounding buildings and underground conditions according to the related data;

as a preferred embodiment of the present invention, the step S3 includes:

s301, determining the positions and the number of tamping points for dynamic compaction replacement of a site, wherein the tamping points are arranged in a regular triangle, square or quincunx shape, the distance between the tamping points can be 2.0-5.0 m, and all the tamping points of a foundation are numbered;

s302, hole leading is carried out at the determined part to be dynamically compacted and replaced, then layered filling is carried out on the hole leading, then repeated tamping is carried out on the layered filling in the hole leading, a method of flushing and slurry extracting is adopted to carry out hole expanding on an interlayer of the soft foundation along the radial direction, the layered filling is continued after the hole expanding is finished, then repeated tamping is carried out on the filling in the interlayer of the soft foundation again, wherein the maximum diameter of the hole expanding is twice of the diameter of the hole leading;

and S303, calculating specific parameters of dynamic compaction replacement, including the number of times of compaction, the interval time of compaction and the fall distance of compaction.

As a preferred embodiment of the present invention, the step S4 includes:

s401, estimating an average ground elevation value possibly generated after dynamic compaction replacement construction in advance, determining the height of the ground before compaction according to the average ground elevation value, and leveling by using a bulldozer;

s402, when the surface soil of the field is soft or the underground water level is high, reducing the underground water level or paving a layer of loose material with a certain thickness on the surface layer, and adopting waterproof measures such as digging a drainage ditch and the like;

s403, when vibration generated by dynamic compaction replacement construction has harmful influence on adjacent buildings or equipment, setting monitoring points, and taking shockproof measures such as digging shock insulation ditches and the like;

s404, setting a working area and a safety range, pulling a warning line to assign a special person to watch, and strictly forbidding the entry of irrelevant persons.

As a preferred embodiment of the present invention, the step S6 includes:

s601, according to a construction drawing and a coordinate control network laid on site, measuring and placing the position of a tamping point by using a theodolite or a total station, and marking out a tamping point central point by using an obvious mark or marking out a tamping point central point by using a lime point;

s602, rechecking the tamping point pay-off before each tamping;

s603, when the rammer is in place, overlapping the center of the rammer and a measured ramming point, and drawing a lime ring by taking the ramming point as the center;

s604, before and during tamping, a sliding staff is used for standing on the hammer top, a special measurer is used for measuring the elevation of the hammer top by using a leveling instrument, each time of tamping is carried out once, the difference value of the two times before and after tamping is the tamping settlement of the tamping, and the final two-stroke tamping settlement meets the design requirement and serves as the tamping stopping standard.

As a preferred embodiment of the present invention, the step S7 includes:

s701, cleaning and leveling the construction site again;

s702, marking tamping points, measuring the elevation of a field, guiding holes at the determined tamping points, filling the guiding holes in a layered mode, repeatedly tamping the layered filling in the guiding holes, reaming the interlayer of the soft foundation in the radial direction by adopting a method of flushing and slurry extracting, continuing to fill the filling in the layered mode after reaming, and repeatedly tamping the filling in the interlayer of the soft foundation again;

s703, positioning the crane, arranging the rammer above a ramming point position, aligning the rammer to the ramming point position by adopting the point rammer with the diameter of 1.5-2.0 m, and measuring the height of the top of the hammer before ramming;

s704, hoisting the rammer to a preset height, starting a unhooking device, putting down a lifting hook after the rammer freely falls down, and measuring the height of the top of the hammer; if the rammer is inclined due to the inclination of the pit bottom, filling the pit bottom in time;

s705, repeatedly tamping, repeatedly backfilling, tamping again after filling, tamping again after tamping, and continuously circulating for 10-30 times;

s706, intermediate checking;

and S707, hammer withdrawing.

As a preferred embodiment of the present invention, the step S706 includes:

s7061, in the construction process, measuring the tamping settlement of each strike by adopting a level gauge every time of tamping, recording the times of filling and the filling amount of each strike, and recording data;

s7062, when the deflection hammer phenomenon is detected, the bottom of the ramming pit is leveled except for adjusting the suspension arm;

s7063, when the rammed pit discharges water, timely backfilling stone, and keeping the distance between the bottom of the hammer and the water level to be not less than 1.0 m; s7064, when the periphery of the tamping pit is excessively raised, timely digging out the raised part;

s7065, checking the backfill stone to meet the design requirement.

As a preferred technical scheme of the invention, gravel sand in a site is adopted as the filler, and graded gravel is mixed according to the gravel ratio of 7:3, so that the gravel is embedded into a soil layer to be reinforced under the action of high energy of dynamic compaction replacement and is tightly combined with surrounding sand, and the compactness of a foundation soil layer is improved.

Compared with the prior art, the invention has the beneficial effects that:

the foundation treatment dynamic compaction replacement reinforcing method uses construction site conventional simple equipment, has simple construction process and wide applicable soil property range, can obtain higher bearing capacity, and can improve the strength of the foundation by 3-5 times; the deformation sedimentation amount is small, the compressibility can be reduced by 5-10 times, and the reinforcement influence depth can reach 8-10 m; the work efficiency is high, the construction speed is high, and the construction period is shortened by half compared with the soil replacement backfill and pile foundation; the reinforcing raw materials are saved; the investment is saved, and the cost is saved by 70 percent compared with the cost of soil replacement and backfilling; compared with the precast pile reinforced foundation, the investment can be saved by 60-70%; compared with sand piles, the method can save investment by 50-70%, can achieve accurate replacement of a target soft stratum, enables a thick and soft soil layer foundation to be consolidated, improves the strength of the foundation, and has higher efficiency.

Drawings

FIG. 1 is an overall step diagram of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present invention provides a technical solution: a dynamic compaction replacement reinforcing method for foundation treatment comprises the following steps:

s1, preparing an early stage project;

s2, designing a reasonable dynamic compaction replacement method according to the field geology and the surrounding environment;

s3, primarily flattening the foundation and adding a plurality of protective measures;

s4, testing ramming and testing ramming effect;

s5, measuring the ground elevation;

s6, measuring and releasing a tamping point;

s7, leveling the site again, and performing full-compaction construction;

and S8, detecting and accepting dynamic compaction.

In this embodiment, preferably, the step S1 includes:

s101, surveying a site and a surrounding environment on site, and determining a part needing dynamic compaction replacement by combining a design drawing;

s102, removing surface soil of the field, namely excavating out the floating soil with the depth of 1.0-1.5 m, and backfilling the leveled field with strongly weathered broken stones to a reference elevation;

s103, preparing construction machinery, field personnel and materials, and having start-up conditions;

s104, determining surrounding buildings and underground conditions according to the related data;

in this embodiment, preferably, the step S3 includes:

s301, determining the positions and the number of tamping points for dynamic compaction replacement of a site, wherein the tamping points are arranged in a regular triangle, square or quincunx shape, the distance between the tamping points can be 2.0-5.0 m, and all the tamping points of a foundation are numbered;

s302, hole leading is carried out at the determined part to be dynamically compacted and replaced, then layered filling is carried out on the hole leading, then repeated tamping is carried out on the layered filling in the hole leading, a method of flushing and slurry extracting is adopted to carry out hole expanding on an interlayer of the soft foundation along the radial direction, the layered filling is continued after the hole expanding is finished, then repeated tamping is carried out on the filling in the interlayer of the soft foundation again, wherein the maximum diameter of the hole expanding is twice of the diameter of the hole leading;

and S303, calculating specific parameters of dynamic compaction replacement, including the number of times of compaction, the interval time of compaction and the fall distance of compaction.

In this embodiment, preferably, the step S4 includes:

s401, estimating an average ground elevation value possibly generated after dynamic compaction replacement construction in advance, determining the height of the ground before compaction according to the average ground elevation value, and leveling by using a bulldozer;

s402, when the surface soil of the field is soft or the underground water level is high, reducing the underground water level or paving a layer of loose material with a certain thickness on the surface layer, and adopting waterproof measures such as digging a drainage ditch and the like;

s403, when vibration generated by dynamic compaction replacement construction has harmful influence on adjacent buildings or equipment, setting monitoring points, and taking shockproof measures such as digging shock insulation ditches and the like;

s404, setting a working area and a safety range, pulling a warning line to assign a special person to watch, and strictly forbidding the entry of irrelevant persons.

In this embodiment, preferably, the step S6 includes:

s601, according to a construction drawing and a coordinate control network laid on site, measuring and placing the position of a tamping point by using a theodolite or a total station, and marking out a tamping point central point by using an obvious mark or marking out a tamping point central point by using a lime point;

s602, rechecking the tamping point pay-off before each tamping;

s603, when the rammer is in place, overlapping the center of the rammer and a measured ramming point, and drawing a lime ring by taking the ramming point as the center;

s604, before and during tamping, a sliding staff is used for standing on the hammer top, a special measurer is used for measuring the elevation of the hammer top by using a leveling instrument, each time of tamping is carried out once, the difference value of the two times before and after tamping is the tamping settlement of the tamping, and the final two-stroke tamping settlement meets the design requirement and serves as the tamping stopping standard.

In this embodiment, preferably, the step S7 includes:

s701, cleaning and leveling the construction site again;

s702, marking tamping points, measuring the elevation of a field, guiding holes at the determined tamping points, filling the guiding holes in a layered mode, repeatedly tamping the layered filling in the guiding holes, reaming the interlayer of the soft foundation in the radial direction by adopting a method of flushing and slurry extracting, continuing to fill the filling in the layered mode after reaming, and repeatedly tamping the filling in the interlayer of the soft foundation again;

s703, positioning the crane, arranging the rammer above a ramming point position, aligning the rammer to the ramming point position by adopting the point rammer with the diameter of 1.5-2.0 m, and measuring the height of the top of the hammer before ramming;

s704, hoisting the rammer to a preset height, starting a unhooking device, putting down a lifting hook after the rammer freely falls down, and measuring the height of the top of the hammer; if the rammer is inclined due to the inclination of the pit bottom, filling the pit bottom in time;

s705, repeatedly tamping, repeatedly backfilling, tamping again after filling, tamping again after tamping, and continuously circulating for 10-30 times;

s706, intermediate checking;

and S707, hammer withdrawing.

In this embodiment, preferably, the step S706 includes:

s7061, in the construction process, measuring the tamping settlement of each strike by adopting a level gauge every time of tamping, recording the times of filling and the filling amount of each strike, and recording data;

s7062, when the deflection hammer phenomenon is detected, the bottom of the ramming pit is leveled except for adjusting the suspension arm;

s7063, when the rammed pit discharges water, timely backfilling stone, and keeping the distance between the bottom of the hammer and the water level to be not less than 1.0 m; s7064, when the periphery of the tamping pit is excessively raised, timely digging out the raised part;

s7065, checking the backfill stone to meet the design requirement.

In this embodiment, preferably, the filler is gravel sand in the ground, and graded gravel is mixed according to the gravel-sand ratio of 7:3, so that the gravel is embedded into the soil layer to be reinforced under the action of high energy of dynamic compaction replacement and is tightly combined with surrounding sand, thereby improving the compactness of the foundation soil layer.

The working principle and the using process of the invention are as follows: early-stage engineering preparation; designing a reasonable dynamic compaction replacement method according to the field geology and the surrounding environment; primarily flattening the foundation and adding a plurality of protection measures; testing ramming and testing ramming effect; measuring the ground elevation; measuring and placing rammed points; leveling the site again, and performing full-compaction construction; detecting and checking and accepting dynamic compaction; the construction site is always provided with simple equipment, the construction process is simple, the applicable soil property range is wide, higher bearing capacity can be obtained, and the strength of the general foundation can be improved by 3-5 times; the deformation sedimentation amount is small, the compressibility can be reduced by 5-10 times, and the reinforcement influence depth can reach 8-10 m; the work efficiency is high, the construction speed is high, and the construction period is shortened by half compared with the soil replacement backfill and pile foundation; the reinforcing raw materials are saved; the investment is saved, and the cost is saved by 70 percent compared with the cost of soil replacement and backfilling; compared with the precast pile reinforced foundation, the investment can be saved by 60-70%; compared with sand piles, the method can save investment by 50-70%, can achieve accurate replacement of a target soft stratum, enables a thick and soft soil layer foundation to be consolidated, improves the strength of the foundation, and has higher efficiency.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.