Earthworks common fault and governance "earthwork disease and governance
A, excavation slope landslide
Phenomenon: in the process of excavation or after excavation, slope local or large landslides, the foundation soil disturbance, reduce the bearing capacity, will seriously affect the safety of buildings.
2. Governance: the groove landslide, collapse after a temporary support measures, should be removed for permanent local slope landslide, the landslide should be removed after use stone fill build by laying bricks or stones or use 2:8, 3:7
Lime soil backfill inlaying, contact with the soil parts step lap, prevent sliding; Or slope will change slow.
Second, backfill soil compactness can not meet the requirements
Phenomenon: after compaction or rolling of backfill soil, its compactness can not meet the design requirements, the deformation under load, strength and stability.
2. The governance:
(1) don't meet requirement of soil is dug in soil, or mixed with lime, gravel compaction reinforcement, etc.
(2) can not meet the compactness of soil due to moisture content is too large, can use scarifying drying, air drying, or even absorbent material such as mixed with dry soil, to consolidate.
(3) for water content of xiaoke with compaction times increased.
Third, bubble water of foundation pit
1. The phenomenon: after excavation, the foundation soil is soaked by water.
2. The governance:
(1) under water bubble of foundation pit, measures should be taken to, to leave the water net
(2) set the intercepting ditch, prevent water brush slope
(3) has been disturbance of soil water immersion, take drainage after dry ramming, or throw fill gravel, small stone compaction; Or changing soil compaction (3:7 lime soil); Or digging silt underpinnings.
Four, slope dig
Interface uneven phenomenon: slope, appear larger calices, slope.
2. Management: the local overbreak, available stone fill build by laying bricks or stones (pulp build by laying bricks or stones) or use the 3:7 lime soil compaction of fill. With the original soil contact parts should be made if steps.
Five, backfill soil foundation walls
Phenomenon: the foundation walls on both sides of the fill or bulldozers to soil, foundation wall crack, fracture, the axis offset, seriously affect the structure performance.
2. Governance: should jointly with the design units, according to the specific circumstances, use the reinforcement measures such as grouting, wai sets, or heavy build by laying bricks or stones of the demolition of the damaged parts.
Six, heart backfill soil subsidence
Phenomenon: local or large room heart backfill soil subsidence, ground level ground surface caused by drum; Cracking damage even collapse.
2. Management: such as floor surface has not been destroyed, can fill in the rubble, filled with mortar pump pressure into the cement mortar to fill dense; If surface has damage, depending on the size and the damage, take partial or all of the rework. Local treatment hammer will play to an empty drum parts are available, and fill in lime soil or clay, gravel mixture compaction, do surface.
Earthworks precontrol quality
A, backfill soil compactness can not meet the requirements
1. The construction preparation:
(1) choose to meet the requirements of the filling soil material. Meet the requirements of the compacted cohesive soil moisture content, can be chosen for the layers of packing; Gravel soil, sandy soil and rock blasting slag (particle size is not more than two-thirds of each layer with thick), can be used as a surface layer of packing; Debris grass and organic matter content is more than 8% of the earth, no compaction requirements can only be used for packing; Mud and silt soil, generally do not affect packing, but in the minor parts of the fill, the treated water content available to meet the requirements of compaction
Silt soil dressing.
(2) with the requirements of the compactness of fill, before construction should be in accordance with the selection of earth material, the compaction method experiments, determined the soil moisture content scope of control, each layer of soil thickness, pressure (ram) number of compaction times, mechanical compaction speed or artificial ramming operation requirements.
(3) write the construction requirements, and the field technical disclosure.
2. The operation process:
(1) basal treatment. Backfill soil should be cleared before basal water and debris; Base for cultivating should fully consolidate; A lot of soft soil basement for water content, drainage drainage or in soil and other measures should be taken.
(2) artificial filled soil from the lowest place, from one end to the other end of the bottom-up hierarchical filling. Virtual height of each layer, using artificial bettle ramming: when sandy soil is not more than 30 cm, cohesive soil is 20 cm; Of ramming tamping machine is not more than 30 cm.
(3) mechanical filling should be bottom-up hierarchical filling. Bulldozers fill each layer virtual height should not be greater than 30 cm. Scraper fill in each layer of virtual height is not more than 30 ~ 50 cm. Auto fill each layer virtual height is not more than 30 ~ 50 cm.
(4) when the backfill should strictly control the moisture content of soil, soil water content of construction should be brought closer to the optimum water content. Material construction of cohesive soil moisture content and the difference between the optimal water content control in 4 ~ + / - 2%.
(5) artificial tamping is performed in a certain direction and one and a half ram pressure rammer, tamping rammer, okay, twice crisscrossed, layered ram. Tamping route should be starting with four edges, and then ram.
(6) before rolling mechanical compaction, appropriate plow with light first bulldozer, tractor, low-speed preloading 4 ~ 5 times, make the surface level; Based on vibration flat crushed stone soil, should first after hydrostatic pressure. When rolling mechanical compaction fill, should control the speed and the compaction times, make it meet the requirements. After the flat grinding roller compacted layer, application of artificial or bulldozers will surface flattening, soil surface works too, should not continue to wet after backfill. Rolling route should be gradually pressure on both sides to the middle.
(7) to fill with compactness requirements, after compaction or cement, to the quality of backfill soil compactness inspection on each floor.
3. Control counter measures:
1) strictly conform to the requirements of the filled soil chosen earth material.
(2)
When backfill soil, should strictly control the moisture content of soil, strengthen the construction before the inspection. When water content is greater than the optimum water content, scarifying, drying and air drying method should be adopted to reduce; Take in backfill soil, or even stir in dry soil, or using other methods to reduce. Moisture content is too low, should be water wet.
(3) should also be strictly controlled during the construction of each layer of soil thickness, pressure (ram) compaction times, (ram) route.
(4) strengthen the earth material, water content, operation and dry density of backfill soil field sampling inspection in accordance with the provisions, strictly the quality control of each work. Second, the excavation slope landslide
1. The construction preparation:
(1) preparation of construction scheme. Clear and deal with the construction area of the ground, underground obstacles.
(2) complete drainage slope direction, good drainage.
(3) axis layout standard pile, positioning control, excavation plaster line and level. And to measure orientation, set to the excavation of foundation excavation width and so on.
(4) to reduce the underground water level, generally fell to the bottom of the channel under the elevation of 0.5 ~ 1.0 m.
2. The operation process:
(1) artificial digging, digging, shallow foundation on slope, should be cut out of the groove edge along the line of contour line, then top-down hierarchical excavation. Each layer of 600 mm deep, each layer should be clear and unearthed, mining step by step; When excavation and soil upper, should guarantee the stability of slope and vertical wall, thrown outside the soil should be 800 mm from trough; Near the underground water level, it shall finish the elevation height of excavation, so as to focus at the drainage; To a certain depth, measuring work timely take out is 500 mm from the bottom of the channel level; Dig to the groove bottom elevation, the axis on both ends of the pile's line, and then repair the tank bottom. Excavation on slope base trough, should be in accordance with the provisions, slope excavation, roughly stratified according to the slope make the slope of line again, every 3 m to do a line, this line to shovel slope; Excavation deep groove, should be in the middle of the slot for about 800 mm apart TuTai, shallow foundation pit excavation of large area, on three sides by the pit excavation and dig out the soil after loading by the freight not dig side; Excavation of the rainy season, should be completed in a piecewise pv films in installment, pay attention to the slope stability, strengthen the slope, support and cofferdam check; Winter excavation, should prevent cold of foundation soil.
(2) mechanical excavation, within 2 m depth of large foundation pit excavation, appropriate USES bulldozer large earthwork can be adopted for the excavation of a scraper; Area is large and deep foundation, the use is more shovel digging, operating surface is narrow, and the groundwater can use backhoe excavator; More than 5 m deep, appropriate stratified excavation, or open channel available shovel with stratified excavation pit; Area is large and deep foundation pit excavation method, can use multiple relay with skip out of the earth; Digging in the groundwater can be used to pull blade or catch a shovel. According to the construction plan of earthwork excavation line, order, storage location requires, such as digging. Large foundation pit bottom elevation is differ, to dig to the entire average elevation, dig deeper parts individually. An excavation depth more than 5 m, appropriate points and 2 ~ 3 layers of excavation, and 10% ~ 15% slope, for digging and transportation vehicles entering and leaving. Pit in larger area and depth are usually adopt layered digging. Large soft soil foundation pit,
"Relay" digging method can be used. Area is not large deep foundation pit, adopts mechanical relay transported earthwork cooperate digging method and artificial and mechanical reasonable, with sleepers pile method, finally make open pit digging machine. Mechanical excavation by deep and shallow, basal and slope should be reserved a layer of 300 ~ 500 mm thickness of the soil by artificial removal of leveling.
3. Control counter measures:
(1) for the permanent slope excavation, should according to the design requirements put slope, generally in 1:1 ~ 1. 5. The use of temporary excavation slope for a longer time, good soil, the slope can ease some.
(2) the excavation of foundation pit (groove) and trench, good soil condition, the underground water level below the bottom elevation, excavation depth within 5 m without support of the slope in the 1-0. 33 ~ 1. 5. During construction period is longer, excavation depth greater than 2 m above, should be made upright wall and support.
(3) make the ground drainage measures to avoid water accumulation. When there are groundwater, measures should be take timely draining.
(4) on the top and soil, stack, the spoilbank the distance to the edge of the excavation slope foot, should according to the nature of the excavation depth, slope gradient and soil. Dry compacted soil, the distance shall be not less than 3 m, soft soil, shall not be less than 5 m.
(5) should be top-down earthwork excavation section stratification, in turn, at any time to finish a certain slope, and to facilitate drainage, avoid to dig the slope toe, slope instability
Third, bubble water of foundation pit
Construction preparation: 1. To dig around the foundation pit drainage and water retaining dike, to prevent surface water flows into the foundation pit. The well point precipitation method, the underground water level drop to the bottom elevation under excavation.
2. The operation process:
(1) digging put slope, slope and slope toe to drain all should keep a certain distance, average of 0.5 ~ 1.0 m; Edge to the slope of permanent excavation slope on water should be keep 5 m distance.
(2) the foundation pit excavation, excavation step by step, step by step a slope, and deepen the gutter and collecting well, check the slope at any time, do not allow the partial steep or dug into the fairy land. Piled up top slope heap of soil materials, to the slope side should keep a certain distance, generally above 0.8 m, pile soil height is not more than 1.5 m.
(3) the excavation of foundation pit in the phreatic aquifer, according to the height of water level, phreatic aquifer thickness and water inflow in phreatic aquifer level low set gutter and collecting well.
(4) digging under the underground water level, and should be high in the bid opening set drainage and water into the feet, and the excavation face, deep gutter and collecting well always maintain a certain difference, lower the underground water level below the excavation face of not less than 0.5 m. When foundation pit depth is larger, high underground water level and the upper soil layers are the strong permeability of soil, or is the same kind of soil, but the upper part of groundwater is flourishing, should adopt layered gutter drainage method, again on the foundation pit slope of 1 ~ 2 layer open trench, layered exclusion of groundwater. Except the gutter drainage of foundation pit, can also be used in a variety of well point precipitation method, the underground water level down to the bottom elevation of the excavation.
3. Control counter measures:
(1) around the foundation pit should be set up drains. When digging put slope, slope and slope toe to drain all should keep a certain distance, average of 0.5 ~ 1.0 m. Edge to the slope of permanent excavation slope on water should be keep 5 m distance.
(2) should be step by step during the excavation of foundation pit excavation, slope step by step, and deepen the gutter and collecting well, check the slope gradient, are not allowed to steep. Piled up top slope heap of soil materials, to the slope side should keep a certain distance, generally above 0.8 m, pile soil height is not more than 1.5 m.
(3) the excavation of foundation pit in the phreatic aquifer, should be in phreatic aquifer level minimum put gutter and collecting well.
(4) below the underground water level digging, should be high standard set foot in excavation gutter and collecting well.
Four, slope dig
1. The construction preparation:
(1) preparation of construction scheme. Clear and deal with the construction area of the ground, underground obstacles. (2) complete drainage slope direction, good drainage.
(3) axis layout standard pile, positioning control, excavation plaster line and level. And to measure orientation, set to the excavation of foundation excavation width and so on. (4)
Lower underground water level, average fell to the bottom of the channel under the elevation of 0.5 ~ 1.0 m.
2. The operation process:
(1) artificial digging, digging, shallow foundation on slope, should be cut out of the groove edge along the line of contour line, then top-down hierarchical excavation. Each layer of 600 mm deep, each layer should be clear and unearthed, mining step by step; When excavation and soil upper, should guarantee the stability of slope and vertical wall, thrown outside the soil should be 800 mm from trough; Near the underground water level, it shall finish the elevation height of excavation, so as to focus at the drainage; To a certain depth, measuring workers take out in time
500 mm flat line the bottom of the channel; Dig to the groove bottom elevation, the axis on both ends of the pile's line, and then repair the tank bottom. Excavation on slope base trough, should be in accordance with the provisions, slope excavation, roughly stratified according to the slope make the slope of line again, every 3 m to do a line, this line to shovel slope; Excavation deep groove, should be in the middle of the slot for about 800 mm apart TuTai, shallow foundation pit excavation of large area, on three sides by the pit excavation and dig out the soil after loading by the freight not dig side; Excavation of the rainy season,
Should be completed in a piecewise pv films in installment, pay attention to the slope stability, strengthen the slope, support and cofferdam check; Winter excavation, should prevent cold of foundation soil.
(2) mechanical excavation, within 2 m depth of large foundation pit excavation, appropriate USES bulldozer large earthwork can be adopted for the excavation of a scraper; Area is large and deep foundation, the use is more shovel digging, operating surface is narrow, and the groundwater can use backhoe excavator; More than 5 m deep, appropriate stratified excavation, or open channel available shovel with stratified excavation pit; Area is large and deep foundation pit excavation method, can use multiple relay with skip out of the earth; In the groundwater
Digging in the available shovel or spade. According to the construction plan of earthwork excavation line, order, storage location requires, such as digging. Large foundation pit bottom elevation is differ, to dig to the entire average elevation, dig deeper parts individually. An excavation depth more than 5 m, appropriate points and 2 ~ 3 layers of excavation, and 10% ~ 15% slope, for digging and transportation vehicles entering and leaving. Pit in larger area and depth are usually adopt layered digging. Large soft soil foundation pit,
"Relay" digging method can be used. Area is not large deep foundation pit, adopts mechanical relay transported earthwork cooperate digging method and artificial and mechanical reasonable, with sleepers pile method, finally make open pit digging machine. Mechanical excavation by deep and shallow, basal and slope should be reserved a layer of 300 ~ 500 mm thickness of the soil by artificial removal of leveling.
3. Control counter measures:
(1) artificial excavation should be end of the qing and unearthed one by one. (2) mechanical excavation should be reserved 0.3 m thick using artificial slope. (3)
To strengthen in the process of excavation of retest, strict localization, set foot in the top edge marks and line, and check by designated personnel.
Five, backfill soil foundation walls
1. The construction preparation:
(1) choose to meet the requirements of the filling soil material. Meet the requirements of the compacted cohesive soil moisture content, can be chosen for the layers of packing; Gravel soil, sandy soil and rock blasting slag (particle size is not more than two-thirds of each layer with thick), can be used as a surface layer of packing; Debris grass and organic matter content is more than 8% of the earth, no compaction requirements can only be used for packing; Mud and silt soil, generally do not affect packing, but in the minor parts of the fill, the treated water content available to meet the requirements of compaction
Silt soil dressing.
(2) with the requirements of the compactness of fill, before construction should be in accordance with the selection of earth material, the compaction method experiments, determined the soil moisture content scope of control, each layer of soil thickness, pressure (ram) number of compaction times, mechanical compaction speed or artificial ramming operation requirements.
(3) write the construction requirements, and the field technical disclosure.
2. The operation process:
(1) basal treatment. Backfill soil should be cleared before basal water and debris; Base for cultivating should fully consolidate; A lot of soft soil basement for water content, drainage drainage or in soil and other measures should be taken.
(2) artificial filled soil from the lowest place, from one end to the other end of the bottom-up hierarchical filling. Virtual height of each layer, using artificial bettle ramming: when sandy soil is not more than 30 cm, cohesive soil is 20 cm; Of ramming tamping machine is not more than 30 cm.
(3) mechanical filling should be bottom-up hierarchical filling. Bulldozers fill each layer virtual height should not be greater than 30 cm. Scraper fill in each layer of virtual height is not more than 30 ~ 50 cm. Auto fill each layer virtual height is not more than 30 ~ 50 cm.
(4) when the backfill should strictly control the moisture content of soil, soil water content of construction should be brought closer to the optimum water content. Material construction of cohesive soil moisture content and the difference between the optimal water content control in 4 ~ + / - 2%.
(5) artificial tamping is performed in a certain direction and one and a half ram pressure rammer, tamping rammer, okay, twice crisscrossed, layered ram. Tamping route should be starting with four edges, and then ram.
(6) before rolling mechanical compaction, appropriate plow with light first bulldozer, tractor, low-speed preloading 4 ~ 5 times, make the surface level; Based on vibration flat crushed stone soil, should first after hydrostatic pressure. When rolling mechanical compaction fill, should control the speed and the compaction times, make it meet the requirements. After the flat grinding roller compacted layer, application of artificial or bulldozers will surface flattening, soil surface works too, should not continue to wet after backfill. From both sides in the pressure gradually to rolling line
Between.
(7) to fill with compactness requirements, after compaction or cement, to the quality of backfill soil compactness inspection on each floor.
(8), but should pay proper attention to based on both sides of the stratified backfill compaction at the same time, the balance of forces. When the backfill elevation is large, without backfill increase support top side. Avoid unilateral backfill soil.
3. Control counter measures: based on both sides with fine earth stratified backfill compaction at the same time. On both sides of the filled soil elevation difference control no more than 30 cm. If encounter central heating ditch or indoor and outdoor backfill elevation difference is bigger, backfill soil on the other side when it temporarily. Foundation wall construction, backfilling construction after reaching a certain intensity. At the same time avoid walking in unilateral temporary a large number of material piling and heavy machinery equipment.
Six, heart backfill soil subsidence
1. The construction preparation:
(1) choose to meet the requirements of the filling soil material. Meet the requirements of the compacted cohesive soil moisture content, can be chosen for the layers of packing; Gravel soil, sandy soil and rock blasting slag (particle size is not more than two-thirds of each layer with thick), can be used as a surface layer of packing; Debris grass and organic matter content is more than 8% of the earth, no compaction requirements can only be used for packing; Mud and silt soil, generally do not affect packing, but in the minor parts of the fill, the treated water content available to meet the requirements of compaction
Silt soil dressing.
(2) with the requirements of the compactness of fill, before construction should be in accordance with the selection of earth material, the compaction method experiments, determined the soil moisture content scope of control, each layer of soil thickness, pressure (ram) number of compaction times, mechanical compaction speed or artificial ramming operation requirements.
(3) write the construction requirements, and the field technical disclosure.
(4) need to pay special attention to in the filling soil is not contain large amounts of organic impurities and large clods.
2. The operation process:
(1) basal treatment. Backfill soil should be cleared before basal water and debris; Base for cultivating should fully consolidate; A lot of soft soil basement for water content, drainage drainage or in soil and other measures should be taken.
(2) artificial filled soil from the lowest place, from one end to the other end of the bottom-up hierarchical filling. Virtual height of each layer, using artificial bettle ramming: when sandy soil is not more than 30 cm, cohesive soil is 20 cm; Of ramming tamping machine is not more than 30 cm.
(3) mechanical filling should be bottom-up hierarchical filling. Bulldozers fill each layer virtual height should not be greater than 30 cm. scraper
Fill in each layer of virtual height is not more than 30 ~ 50 cm. Auto fill each layer virtual height is not more than 30 ~ 50 cm.
(4) when the backfill should strictly control the moisture content of soil, soil water content of construction should be brought closer to the optimum water content. Material construction of cohesive soil moisture content and the difference between the optimal water content control in 4 ~ + / - 2%.
(5) artificial tamping is performed in a certain direction and one and a half ram pressure rammer, tamping rammer, okay, twice crisscrossed, layered ram. Tamping route should be starting with four edges, and then ram.
(6) before rolling mechanical compaction, appropriate plow with light first bulldozer, tractor, low-speed preloading 4 ~ 5 times, make the surface level; Based on vibration flat crushed stone soil, should first after hydrostatic pressure. When rolling mechanical compaction fill, should control the speed and the compaction times, make it meet the requirements. After the flat grinding roller compacted layer, application of artificial or bulldozers will surface flattening, soil surface works too, should not continue to wet after backfill. Rolling route should be gradually pressure on both sides to the middle.
(7) to fill with compactness requirements, after compaction or cement, to the quality of backfill soil compactness inspection on each floor.
3. Control counter measures:
(1) appropriate backfill material selection, careful control of soil water content in the optimal range, in strict accordance with the provisions of stratified backfill compaction, and sampling inspection compactness.
(2) before the construction, should the original natural soft soil layer for processing.
(3) heart backfill soil depth is greater than 1.5 m, outside the building wall seepage control measures should be taken to backfill soil.
(4) use to demand higher heart backfill soil, large room should use mechanical first former dense natural soil pressure, and then backfill soil.
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