Chapter I: Preface

The absence of any but fragmentary information on EARTH-SLIPS AND SUBSIDENCES UPON PUBLIC WORKS, one of the most annoying and expensive occurrences in engineering construction, has prompted the author to write this book as a vade-mecum for those in charge of such undertakings as _Railways_, _Docks_, _Canals_, _Roads_, _Waterworks_, _River-banks_, _Reclamation embankments_, _Drainage works_, &c., and also to fill, however imperfectly, somewhat of an hiatus in engineering literature.

The theory of the lateral pressure of earthwork is not examined, as it is well understood; the intention being to concisely describe the chief causes of slips and subsidences in different earths and many points requiring attention, to call to remembrance some soils especially treacherous and unstable, and to name various preventive measures and effectual remedies.

A reference to the table of contents and the index will demonstrate the comprehensiveness of the subject, for it involves in the various practical applications the science of geology, physical geography, meteorology, the laws of pressure of earth, some chemical and botanical, and other scientific knowledge.

It is scarcely necessary to observe that no exhaustive treatise is herein attempted, for that would indeed be an Herculean task; but in this volume the endeavour has been made to present reliable information, the result of experience, research, considerable labour, and lengthened observation.

J. N.

LONDON. _March, 1890_.

CONTENTS.

CHAPTER I.

PAGES

INTRODUCTION—GENERAL CONSIDERATIONS—ENUMERATION OF THE PRIMARY
CAUSES OF SLIPS AND SUBSIDENCES IN CUTTINGS AND EMBANKMENTS,
AND EARTHWORKS CONSTRUCTED TO CONTAIN OR EXCLUDE WATER—SOME
DOMINANT PRINCIPLES TO BE REMEMBERED IN DETERMINING THE
LOCATION OF EARTHWORKS 1–12

CHAPTER II.

THE PROBABILITY OF A SLIP—TIME OF THE MOST FREQUENT
OCCURRENCE—SOME CONDITIONS UNDER WHICH SLIPS AND SUBSIDENCES
IN CUTTINGS AND EMBANKMENTS MAY BE EXPECTED IN DIFFERENT
EARTHS, SUCH AS ROCK, CHALK, SAND, GRAVEL, CLAY, &C.,
&C.—NOTES ON THE SLOPES OF REPOSE 13–49

CHAPTER III.

THE GENERAL EFFECT OF A SLIP IN A CUTTING OR AN
EMBANKMENT—ENUMERATION AND CONSIDERATION OF SOME PROTECTIVE
AND REMEDIAL WORKS—TREATMENT OF THE SLIPPED EARTH 50–64

CHAPTER IV.

NOTES ON THE PERCOLATION OF WATER—SYSTEMS OF DRAINAGE OF
CUTTINGS AND EMBANKMENTS IN DIFFERENT KINDS OF EARTH AND
UNDER DIVERSE CONDITIONS—THE CONSTRUCTION OF CULVERTS,
PIPE-DRAINS, TRENCHES, DITCHES, AND CATCHWATER DRAINS 65–86

CHAPTER V.

APPROXIMATE SAFE MAXIMUM LOAD UPON DIFFERENT EARTHS—NORMAL
PRESSURE OF THE EARTH—THE SAFE MAXIMUM LOAD UPON DEPOSITED
EARTH—APPROXIMATE SAFE MAXIMUM HEIGHT OF AN EMBANKMENT 87–97

CHAPTER VI.

SLOPES, GENERAL CONSIDERATIONS—TABLE SHOWING THE GENERAL RANGE
OF SLOPES—TABLE OF COEFFICIENTS OF FRICTION—NOTES ON THE
COHESION OF EARTH—FORM OF A SLOPE—SOME CONDITIONS GOVERNING
THE NECESSARY INCLINATION—WIDENING EARTHWORKS WITHIN THE
ORIGINAL FENCES 98–114

CHAPTER VII.

NOTES UPON THE PRESERVATION OF THE FOOT OF A SLOPE—VARIOUS
METHODS OF COVERING AND SUPPORTING A SLOPE—PROTECTION FROM
SNOW-DRIFTS—THE FORMATION WIDTH OF CUTTINGS AND
EMBANKMENTS—THE DELETERIOUS EFFECTS OF VIBRATION 115–141

CHAPTER VIII.

EARTHWORKS IN OR UPON SIDELONG GROUND—SOME INSECURE
CONDITIONS—PRECAUTIONARY MEASURES—EMBANKMENTS UPON SOFT
GROUND—EMBANKMENTS COMPOSED OF SOFT EARTH—THE PROMOTION OF
STABILITY AND CONSOLIDATION 142–155

CHAPTER IX.

THE DEPOSITION OF AN EMBANKMENT—PREPARATION OF THE GROUND UPON
WHICH AN EMBANKMENT HAS TO BE DEPOSITED—METHODS OF
PROCEDURE—CONSIDERATION OF SOME OF THE DIFFERENT SYSTEMS—THE
EFFECT OF THE HEIGHT OF A TIP AND THE LENGTH OF A LEAD—THE
STEAM NAVVY AND EMBANKMENTS 156–170

CHAPTER X.

NOTES UPON THE LOCATION, PRESERVATION, AND PROTECTION OF SEA,
ESTUARY, RECLAMATION, CANAL, AND RESERVOIR EMBANKMENTS OF
EARTH CONSTRUCTED TO CONTAIN OR EXPEL WATER 171–197

CHAPTER XI.

NOTES UPON THE FAILURE OF DOCK AND OTHER WALLS FROM A FORWARD
MOVEMENT OF THE EARTH FILLING OR BACKING—CONSIDERATION OF THE
CAUSES OF SUCH ACTION AND SOME PREVENTIVE AND REMEDIAL
MEASURES 198–215

CHAPTER XII.

NOTES UPON SLIPS OF EARTH, SUBSIDENCES, AND MOVEMENT IN
FOUNDATIONS CAUSED BY “BOILS,” OR AN UPWARD RUSH OF WATER IN
LOOSE EARTHS—CONSIDERATION OF SOME PRECAUTIONARY AND REMEDIAL
OPERATIONS 216–225

EARTHWORK SLIPS AND SUBSIDENCES UPON PUBLIC WORKS.

CHAPTER I.