Moân COÂNG TRÌNH TREÂN ÑAÁT YEÁU BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

CHÖÔNG 1 Gia cöôøng ñaát yeáu vôùi phöông phaùp giaûm heä soá roãng CHÖÔNG 2 Gia cöôøng ñaát yeáu vôùi phöông phaùp troän vôùi chaát keát dính - grouting CHÖÔNG 3 Gia cöôøng ñaát yeáu vôùi phöông phaùp taêng cöôøng vaät lieäu chòu keùo (vaûi – væ ÑKT) CHÖÔNG 4 Coïc vaø ñaøo saâu trong ñaát yeáu BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Taøi lieäu tham khaûo: 1.Ground improvement, B. Indraratna – J. Chu, Geotechnics of soft soils, M. Karsttunen – M. Loni, Excavations and Foundations in soft soils, Hans-Georg Kempfert, Berhane Gebreselassie, Applied soil machanics, Sam Helwany, Engineering treatment of soils, F.G. Bell, Neàn moùng, Chaâu Ngoïc Aån, 2010 BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

SEÙT Nhaän daïng taïi coâng tröôøng Söùc chòu neùn moät truïc, q unc kN/m 2 RAÁT MEÀM aán caû naém tay vaøo ñaát deã daøng < 25 MEÀM aán caû ngoùn caùi vaøo ñaát deã daøng 25 – 50 DEÛO aán caû ngoùn caùi vaøo ñaát caàn coù löïc 50 – 100 CÖÙNG aán maïnh ngoùn caùi laøm loõm ñaát 100 – 200 RAÁT CÖÙNG aán maïnh baèng moùng ngoùn caùi ñeå daáu 200 – 400 RAÉN khoù ñeå daáu treân ñaát baèng caùch aán maïnh ngoùn caùi > 400 BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

CAÙT (tin caäy)SEÙT (khoâng tin caäy laém) N (SPT) < 2 RAÁT MEÀM 0 - 4RAÁT RÔØI2 – 4 MEÀM 4 – 10RÔØI4 – 8 DEÛO 10 – 30CHAËT TB8 – 15 CÖÙNG 30 – 50CHAËT15 – 30 RAÁT CÖÙNG > 50RAÁT CHAËT> 30 RAÉN BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

CHÖÔNG 1 Gia cöôøng ñaát yeáu vôùi phöông phaùp giaûm heä soá roãng ÑAÁT YEÁU Theo QP BUØN laø ñaát loaïi seùt ôû giai ñoaïn ñaàu hình thaønh, ñöôïc taïo ra nhö traàm tích caáu truùc trong nöôùc khi coù caùc quaù trình vi sinh vaät vaø, ôû keát caáu töï nhieân, coù ñoä aåm vöôït quaù giôùi haïn loûng vaø heä soá roãng vöôït quaù caùc giaù trò sau: buøn aù caùt khi e > 0,9; buøn aù seùt khi e > 1; buøn seùt khi e> 1,5 BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Compaction at a highway off-ramp These photos are from the construction of a highway off-ramp in Davis, California, in This relatively small earthwork job was performed with very few pieces of equipment (a cat, water truck, grader, and the trucks that transported fill soils to the site). BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

This cat is equipped with a blade for shaping the roadway and sheepsfoot rollers for compacting the clayey soils. Fill materials were brought to the site by trucks that spread the materials out in roughly 6 to 8 inch thick layers. The cat spread the material out evenly and compacted it at the same time. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

A side view of the cat. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The water truck sprays the earth during compaction to condition the soil to near its optimum moisture content for compaction, and to control dust at the site. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The operators of the water truck and cat sequence their passes across the site. A grader was later used for final shaping of the roadway surface BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Roller Compactors As soil embankments are constructed, the fill is spread in layers and compacted in order to increase strength and reduce compressibility of the soil. The loose lift thickness is usually 8 inches to 12 inches. These photos show four different types of rollers suitable for compacting cohesive (clayey) soils and cohesionless soils (sands and gravels). BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Here a pneumatic rubber-tired roller is compacting clay soil. Clays are more difficult to compact than sands and gravels, because they must be brought to the right range of water content before they can be compacted to high densities. Static pressure, as exerted by the wheels of this rubber-tired roller, compacts clays well. (Photo by Caterpillar). BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

This photo shows a vibratory steel-wheeled roller compacting sand. Vibration is more effective for compacting sands and gravels than static pressure. Water conditioning is not as important for compacting sands and gravels as it is for compacting clays. The total force applied by a vibratory roller is equal to the weight of the roller plus the dynamic vibratory force. (Photo by Caterpillar). BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Here a vibratory padded drum roller (similar to a sheepsfoot roller) is compacting clay. The protrusions (pads) on the drum press into the soil when it is loose, and compact the layer from the bottom up. After a few passes, when the fill has been densified to some degree, the roller "walks out," and the entire weight is supported on the pads resting on top of the fill, which results in higher compaction pressures on the soil. (Photo by Caterpillar). BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

This photo shows a tamping-foot roller compacting clay. Like a padded drum roller or a sheepsfoot roller, the feet protruding from the drums penetrate into the fill when it is loose, compacting the fill from the bottom up. (Photo by Caterpillar). BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Loã ñuïc trong ñaát Baûng ñeá Coâne theùp Van môû Caùt chuaån BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Loã ñuïc trong ñaát Baûng ñeá Tuùi cao su theùp Bôm tay Bình chöùa nöôùc coù vaïch ño theå tích BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

C«ng nghÖ dïng trong kiÓm tra chÊt l­îng ®Êt nÒn sau khi c¶i t¹o/gia cè (®ång vÞ phãng x¹)

BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Ñöôøng ñi cuûa photon Nguoàn Ñaàu nhaän BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Deep Dynamic Compaction Natural soil deposits and undocumented fills can be densified by dropping large weights from great heights repeatedly on the ground surface. Because the energy imparted is considerable, compaction can be achieved at significant depths below the ground surface. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

ÑAÀM CHAËT BAÈNG TAÏ RÔI BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Lµm chÆt ®Êt b»ng ®Çm/lu lÌn trªn mÆt hoÆc chiÒu s©u Cã c¸c ph­¬ng ph¸p sau: Lu lÌn, ®Çm nÆng r¬i tõ cao xuèng; LÌn chÆt ®Êt qua lç khoan (cäc c¸t, cäc ®¸ d¨m, cäc ®Êt v«i xim¨ng, næ m×n..); Cè kÕt ®éng (dynamic consolidation). C¸c c«ng nghÖ thi c«ng nãi trªn hiÖn ®· ph¸t triÓn rÊt cao nhê thiÕt bÞ thi c«ng ngµy cµng hoµn thiÖn vµ ph­¬ng ph¸p kiÓm tra ngµy cµng cã ®é tin cËy cao. Nh÷ng th«ng sè kiÓm tra chÝnh nh­ ®· tr×nh bµy ë ®Çu môc III vµ chi tiÕt th× theo nh÷ng tiªu chuÈn thi c«ng cô thÓ cña tõng ph­¬ng ph¸p. VÒ nguyªn t¾c : ®èi víi c«ng tr×nh quan träng cÇn tiÕn hµnh thÝ nghiÖm nÐn vµ c¾t cho ®Êt ë ®é ®Çm chÆt kh¸c nhau, trªn c¬ së ®ã x©y dùng biÓu ®å quan hÖ gi÷a: Lùc dÝnh vµ ®é chÆt (th«ng qua  kh« hay hÖ sè ®Çm chÆt k); Gãc ma s¸t vµ ®é chÆt; M« ®un biÕn d¹ng/c­êng ®é vµ ®é chÆt. Khi ch­a cã sè liÖu thÝ nghiÖm cã thÓ dïng c¸c sè liÖu tham kh¶o ë c¸c b¶ng sau ®©y trong thiÕt kÕ s¬ bé ®Ó khèng chÕ chÊt l­îng. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

ÑAÀM CHAËT BAÈNG TAÏ RÔI This mass of concrete, weighing about 12,000 pounds, was used for deep dynamic compaction at the site of an oil storage tank farm on Hokkaido, in Japan. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Here the mass has been lifted to a height of about 50 feet, and is ready to be dropped. When it hits the surface of the ground, the blow will impart about 600,000 foot-pounds of energy. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

These craters are the result of dropping the weight. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The craters were surveyed to determine the effects of the treatment. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Vibroreplacement Stone Columns at MIA Dam These photos are of vibroreplacement stone column construction at Mormon Island Auxiliary Dam east of Sacramento, California, in The purpose of the stone columns is to reduce the potential for liquefaction of the subsurface soils during an earthquake. Vibroreplacement stone columns improve the resistance of cohesionless soils to liquefaction by several mechanisms. The primary mechanism of treatment is the densification of the native soil. Secondary benefits may also come from the reinforcing effects of the stone columns (e.g.,. they are usually stiffer than the surrounding soil), an increase in the in-situ horizontal stress (e.g., due to the packing of stone in the column), and the drainage of earthquake-induced pore water pressures through the stone columns. “COÏC VAÄT LIEÄU RÔØI”  “COÄT ÑAÙ” BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

This schematic shows the various steps in the vibroreplacement process. First, the vibroflot penetrates the ground to the desired depth. Stone is then progressively introduced to the hole, and the vibroflot is alternately raised and lowered to produce a packed stone column. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

A crane lifts the vibrating probe or vibroflot. A front-end loader is feeding coarse stone (aggregate) in at the top of the hole around the vibroflot. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

End of vibroflot. The tube on the right is used to deliver stone to the tip of the probe while it is in the ground. The small tube on the left is a water/air jet to assist the vibroflot in penetrating to the desired depth and in flushing the hole as necessary. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Lifting the vibroflot BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Vibroflot being lifted in preparation for constructing a stone column. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The water jet has been turned on and the vibroflot is ready to start penetrating the ground. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The vibroflot begins to penetrate the ground. The horizontal vibrations of the vibroflot are what cause the water to splash around. The water jet assists the probe in penetrating to the full desired depth. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

A front-end loader places stone into a hopper on the crane BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The hopper on the crane brings the stone to the top of the vibroflot where it can be transmitted down a chute to the tip of the vibroflot. The front-end loader also dumps stone at the top of the hole. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Soils in zones A and B can be compacted by the deep vibratory compaction method Vibro Compaction (also called “Vibroflotation”), while soils of zones C and D cannot be compacted by vibration alone. Soils in zone C are often found on sites where soil liquefaction due to earthquakes is of concern. These soils can be compacted during the installation of Stone Columns. Soils in zone D are not compactable by vibration, but can be substantially reinforced, stiffened and drained by installing Stone Columns.(CẦN CÓ BAO CỘT ĐÁ) BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Requirements for the soil to achieve good compaction by vibration: The soil must be permeable enough to allow rapid drainage of the pore water during the compaction process. The permeability is high enough for all granular soils with less than 12 % fines smaller than sieve #200 (0.074 mm) AND less than 2% clay. The friction angle of the soil must be high enough to permit the passage of the compacting shear waves. This requirement is usually satisfied if the soil is well graded. The sand or gravel should not be easily crushable (carbonate content in form of shells) or contain very platy mica minerals that would increase soil compressibility. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The Ethiopian government, in an effort to increase local food production, is constructing earth dams to store water for irrigation. These micro dams, which can reach heights of 20 meters, have largely been constructed by hand labor as part of the work-for-food program in which the food payment is often Canadian wheat. While this program has provided much-needed work and food, it has not always resulted in the desired quality control and material compaction of the dams. The hand-placed rip-rap however is beautiful. There is now a desire in the Tigray region to design and construct these dams on a more technical basis, and thus the desire for a workshop. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Lime Treatment These photos show the use of lime to treat expansive soils during site work for a large retail outlet in the east Bay Area in The building will have a slab on grade, and the native soils are susceptible to swelling and expansion upon wetting (high plasticity clays). Hydrated lime reacts with the clay minerals in the soil, reducing its potential for swelling and expansion upon wetting. A pad or layer of lime-treated soil will be constructed over the entire building footprint prior to construction of the slab foundation. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

A truck sprays lime powder uniformly on the ground surface after it has been graded, but before it is compacted. The area is divided into sections by the wooden stakes to help guide the operators. The amount of lime depends on the soil characteristics, but is typically a few percent of the treated soil's dry weight. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

This self-loading scraper is equipped with mixers inside its bucket. It scrapes up soil that has already been sprayed with lime, mixes it within its bucket, and then spreads it back over the ground surface. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

A rear view of the same scraper. The mixing blades can be seen under the rear end of the bucket. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

The caterpillar on the left grades the treated areas and compacts the soil with its sheepsfoot rollers. A water truck (white, distant center of photo) sprays the soil with water to achieve the target water content prior to compaction. BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Tyû dieän tích thay theá A s -dieän tích ngang cuûa coïc vaät lieäu rôøi A c -dieän tích ngang cuûa ñaát seùt xung quanh coïc C 1 -haèng soá phuï thuoäc daïng boá trí coïc vaät lieäu rôøi. Neáu coïc boá trí theo löôùi hình vuoâng thì C 1 =  /4 theo daïng tam giaùc ñeàu thì S D BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Khi ñaát hoãn hôïp chòu taûi, nhieàu nghieân cöùu ñaõ chæ ra raèng söï taäp trung öùng suaát xuaát hieän treân coïc vaät lieäu rôøi seõ keøm theo giaûm öùng suaát trong ñaát seùt meàm ôû xung quanh. Ñieàu naøy coù theå giaûi thích laø khi chaát taûi, ñoä luùn cuûa coïc vaät lieäu rôøi vaø ñaát ôû xung quanh xaáp xæ nhau. Söï phaân boá öùng suaát thaúng ñöùng trong phaïm vi moät ñôn nguyeân (goàm coïc vaø ñaát xung quanh) ñöôïc bieåu thò baèng heä soá taäp trung öùng suaát n: Vôùi :  s -öùng suaát treân coïc vaät lieäu rôøi;  c -öùng suaát treân ñaát dính xung quanh. Ñoä lôùn taäp trung öùng suaát cuõng phuï thuoäc vaøo quan heä giöõa ñoä cöùng cuûa coïc vaät lieäu rôøi vaø cuûa ñaát xung quanh. Theo thu thaäp cuûa Barksdal vaø Bachus (1983), heä soá taäp trung öùng suaát bieán ñoåi theo tyû dieän tích thay theá trong khoaûng töø 2 ñeán 5. ÖÙng suaát trung bình  treân dieän tích moät ñôn nguyeân töông öùng vôùi tyû dieän tích thay theá ñaõ cho a s, ñöôïc bieåu thò nhö sau:  =  s a s +  c (1-a s ) BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

NÒn gia cè BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

CÔ CHEÁ PHAÙ HOAÏI Trong thöïc teá, cột vaät lieäu rôøi thöôøng ñöôïc xaây döïng xuyeân qua toaøn boä lôùp ñaát seùt yeáu naèm treân ñòa taàng raén chaéc (gaàn gioáng coïc choáng). Cuõng coù theå laøm nhöõng coät maø muõi cuûa chuùng chæ trong phaïm vi lôùp seùt yeáu (gioáng coïc treo). Caùc coät vaät lieäu rôøi coù theå bò phaù hoaïi rieâng töøng coät hoaëc caû nhoùm. Cô cheá phaù hoaïi ñoái vôùi moät coät ñôn ñöôïc minh hoïa treân hình. a) phình ra beân;b) caét qua coät ;c) tröôït coät BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Coät coù bao BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

GIA TAÛI TRÖÔÙC Gia taûi thöôøng ñöôïc duøng trong kyõ thuaät neàn moùng laø nhaèm laøm cho neàn ñaát yeáu luùn tröôùc, ñaát neàn seõ giaûm ñoä roãng töông öùng vôùi taûi gia taêng treân maët ñaát, söùc chòu ñöïng seõ gia taêng. Vaán ñeà cuûa baøi toaùn laø choïn gia taûi sao cho phuø hôïp vôùi aùp löïc coâng trình taùc ñoäng leân neàn trong töông lai vaø döï ñoaùn caùc bieän phaùp thi coâng gia taûi thích hôïp. * Vôùi ñaát rôøi vaø ñaát yeáu khoâng baõo hoøa nöôùc thôøi gian ñaït ñoä luùn oån ñònh seõ ngaén. * Vôùi ñaát neàn yeáu laø ñaát loaïi seùt baõo hoøa nöôùc thì thôøi gian luùn seõ phuï thuoäc vaøo toác ñoä coá keát thaám vaø bò chi phoái theo phöông trình vi phaân coá keát thaám BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

pp z u ’’ h=2H pp H öôùng thoaùt nöôùc Khi U z < 60%  Khi U z > 60%  T z = 1,781 – 0,933log(100-U z ) BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Ngöôøi ta ñaép moät lôùp caùt ñeàu kín khaép taïo moät aùp löïc neùn tröôùc  p = 115kPa leân treân lôùp seùt daày 6m coù caùc ñaëc tröng sau: p 0 =21 MPa; C c = 0.28; e 0 = 0.9; C v = 0.36 m 2 /thaùng Neàn laø ñaát seùt coá keát thöôøng (NC) A/ Tính toång ñoä luùn do coá keát sô caáp B/ Tính ñoä luùn do coá keát sô caáp sau 9 thaùng A/ Toång ñoä luùn do coá keát sô caáp = m = m B/ Vôùi C v = 0.36 m 2 /thaùng; H=3m (thoaùt nöôùc theo hai bieân); t= 9 thaùng.  U v = 67% = S t /S  S t =112.4 mm BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

GIA TAÛI TRÖÔÙC keát hôïp GIEÁNG CAÙT Gia taûi thöôøng ñöôïc duøng trong kyõ thuaät neàn moùng laø nhaèm laøm cho neàn ñaát yeáu luùn tröôùc, ñaát neàn seõ giaûm ñoä roãng töông öùng vôùi taûi gia taêng treân maët ñaát, söùc chòu ñöïng seõ gia taêng. Vaán ñeà cuûa baøi toaùn laø choïn gia taûi sao cho phuø hôïp vôùi aùp löïc coâng trình taùc ñoäng leân neàn trong töông lai vaø döï ñoaùn caùc bieän phaùp thi coâng gia taûi thích hôïp. * Vôùi ñaát rôøi vaø ñaát yeáu khoâng baõo hoøa nöôùc thôøi gian ñaït ñoä luùn oån ñònh seõ ngaén. * Vôùi ñaát neàn yeáu laø ñaát loaïi seùt baõo hoøa nöôùc thì thôøi gian luùn seõ phuï thuoäc vaøo toác ñoä coá keát thaám vaø bò chi phoái theo phöông trình sau: z 2R Höôùng thaám nöôùc krkr kzkz kzkz 2R 2r h=2H Phaûn aùp GIA TAÛI TRÖÔÙC pp BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

N GUYEÂN LYÙ HOAÏT ÑOÄNG GIEÁNG CAÙT - BAÁC THAÁM - SAND DRAINS BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Phöông trình vi phaân coá keát thaám ba chieàu coù daïng phaàn thaám xuyeân taâm phaàn thaám thaúng ñöùng Lôøi giaûi cuûa Carillo (1942) cho ñoä coá keát toång hôïp U z,r cuûa thaám ñöùng Uz vaø thaám ngang Ur U z,r = 1 – (1-U r )(1-U z ) BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

TrUrUr n=5n=10n=15n=20n=25n=30n=35n= BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

C/ Trong thí duï treân, tính ñoä luùn do coá keát sô caáp sau 9 thaùng khi coù boá trí gieáng caùt baùn kính r=0.1m, caùch khoaûng d=3m vaø C vz = C vr. Phaàn c n = d/2r= 3/0.2 =15  =0.36 Vaäy theo Carillo: U v,r = 1- (1-U v )(1-U r ) = 1 – (1-0.67)(1 – 0.77) = 0.924=92.4% St = 92.4% S = 92.4% mm = 155 mm BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Baác thaám BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Baác thaám BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Baác thaám BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

C AØI ÑAËT BAÁC THAÁM TRONG ÑAÁT YEÁU BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

GIA TAÛI TRÖÔÙC BAÈNG HUÙT CHAÂN KHOÂNG BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Ñoä luùn theo thôùi gian coù vaø khoâng coù thieát bò thoaùt nöôùc thaúng ñöùng BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Thieát bò thaám ngang BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Thieát bò thaám ngang BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN

Coâng trình beå chöùa ñaët treân neàn gia taûi baèng huùt chaân khoâng BAØI GIAÛNG A Pr.Dr. CHAÂU NGOÏCAÅN